diff --git a/backend/genesys/device.cpp b/backend/genesys/device.cpp
index 996409fad..6b708b5fb 100644
--- a/backend/genesys/device.cpp
+++ b/backend/genesys/device.cpp
@@ -103,21 +103,6 @@ ImagePipelineNodeBytesSource& Genesys_Device::get_pipeline_source()
     return static_cast<ImagePipelineNodeBytesSource&>(pipeline.front());
 }
 
-uint8_t Genesys_Device::read_register(uint16_t address)
-{
-    return interface->read_register(address);
-}
-
-void Genesys_Device::write_register(uint16_t address, uint8_t value)
-{
-    interface->write_register(address, value);
-}
-
-void Genesys_Device::write_registers(Genesys_Register_Set& regs)
-{
-    interface->write_registers(regs);
-}
-
 UsbDevice& Genesys_Device::get_usb_device()
 {
     if (interface->is_mock())
@@ -128,9 +113,9 @@ UsbDevice& Genesys_Device::get_usb_device()
 void apply_reg_settings_to_device(Genesys_Device& dev, const GenesysRegisterSettingSet& regs)
 {
     for (const auto& reg : regs) {
-        uint8_t val = dev.read_register(reg.address);
+        uint8_t val = dev.interface->read_register(reg.address);
         val = (val & ~reg.mask) | (reg.value & reg.mask);
-        dev.write_register(reg.address, val);
+        dev.interface->write_register(reg.address, val);
     }
 }
 
diff --git a/backend/genesys/device.h b/backend/genesys/device.h
index 9f4f4e68d..4c6d99641 100644
--- a/backend/genesys/device.h
+++ b/backend/genesys/device.h
@@ -361,10 +361,6 @@ struct Genesys_Device
 
     std::unique_ptr<ScannerInterface> interface;
 
-    std::uint8_t read_register(std::uint16_t address);
-    void write_register(std::uint16_t address, std::uint8_t value);
-    void write_registers(Genesys_Register_Set& regs);
-
     UsbDevice& get_usb_device();
 
     UsbDevice usb_dev;
diff --git a/backend/genesys/genesys.cpp b/backend/genesys/genesys.cpp
index b34ad04aa..78ad2c39d 100644
--- a/backend/genesys/genesys.cpp
+++ b/backend/genesys/genesys.cpp
@@ -1530,7 +1530,7 @@ static void genesys_shading_calibration_impl(Genesys_Device* dev, const Genesys_
         sanei_genesys_set_motor_power(dev->calib_reg, motor);
     }
 
-    dev->write_registers(dev->calib_reg);
+    dev->interface->write_registers(dev->calib_reg);
 
     if (is_dark) {
         // wait some time to let lamp to get dark
@@ -1735,7 +1735,7 @@ static void genesys_dark_white_shading_calibration(Genesys_Device* dev,
     sanei_genesys_set_lamp_power(dev, sensor, dev->calib_reg, true);
     sanei_genesys_set_motor_power(dev->calib_reg, motor);
 
-    dev->write_registers(dev->calib_reg);
+    dev->interface->write_registers(dev->calib_reg);
 
     dev->cmd_set->begin_scan(dev, sensor, &dev->calib_reg, false);
 
@@ -3184,7 +3184,7 @@ static void genesys_start_scan(Genesys_Device* dev, bool lamp_off)
     }
 
     // now send registers for scan
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
     // start effective scan
     dev->cmd_set->begin_scan(dev, sensor, &dev->reg, true);
@@ -4906,7 +4906,7 @@ sane_close_impl(SANE_Handle handle)
   s->dev->clear();
 
     // LAMP OFF : same register across all the ASICs */
-    s->dev->write_register(0x03, 0x00);
+    s->dev->interface->write_register(0x03, 0x00);
 
     catch_all_exceptions(__func__, [&](){ s->dev->usb_dev.clear_halt(); });
 
diff --git a/backend/genesys/gl124.cpp b/backend/genesys/gl124.cpp
index f0f61cc1a..2b03a7b5a 100644
--- a/backend/genesys/gl124.cpp
+++ b/backend/genesys/gl124.cpp
@@ -65,9 +65,9 @@ static void gl124_homsnr_gpio(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
 
-    uint8_t val = dev->read_register(REG_0x32);
+    uint8_t val = dev->interface->read_register(REG_0x32);
     val &= ~REG_0x32_GPIO10;
-    dev->write_register(REG_0x32, val);
+    dev->interface->write_register(REG_0x32, val);
 }
 
 /** @brief set all registers to default values .
@@ -458,7 +458,7 @@ void CommandSetGl124::set_fe(Genesys_Device* dev, const Genesys_Sensor& sensor,
       dev->frontend = dev->frontend_initial;
     }
 
-    val = dev->read_register(REG_0x0A);
+    val = dev->interface->read_register(REG_0x0A);
 
   /* route to correct analog FE */
     switch ((val & REG_0x0A_SIFSEL) >> REG_0x0AS_SIFSEL) {
@@ -788,8 +788,8 @@ static void gl124_init_optical_regs_scan(Genesys_Device* dev, const Genesys_Sens
                                  !(session.params.flags & SCAN_FLAG_DISABLE_LAMP));
 
     // BW threshold
-    dev->write_register(REG_0x114, dev->settings.threshold);
-    dev->write_register(REG_0x115, dev->settings.threshold);
+    dev->interface->write_register(REG_0x114, dev->settings.threshold);
+    dev->interface->write_register(REG_0x115, dev->settings.threshold);
 
   /* monochrome / color scan */
     r = sanei_genesys_get_address (reg, REG_0x04);
@@ -862,9 +862,9 @@ static void gl124_init_optical_regs_scan(Genesys_Device* dev, const Genesys_Sens
         r->value &= ~REG_0x01_TRUEGRAY;
         if (session.enable_ledadd) {
             r->value |= REG_0x01_TRUEGRAY;
-            dev->write_register(REG_TRUER, 0x80);
-            dev->write_register(REG_TRUEG, 0x80);
-            dev->write_register(REG_TRUEB, 0x80);
+            dev->interface->write_register(REG_TRUER, 0x80);
+            dev->interface->write_register(REG_TRUEG, 0x80);
+            dev->interface->write_register(REG_TRUEB, 0x80);
         }
     }
 
@@ -1030,7 +1030,7 @@ void CommandSetGl124::set_powersaving(Genesys_Device* dev, int delay /* in minut
 static void gl124_start_action(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x01);
+    dev->interface->write_register(0x0f, 0x01);
 }
 
 static void gl124_stop_action(Genesys_Device* dev)
@@ -1048,7 +1048,7 @@ static void gl124_stop_action(Genesys_Device* dev)
       sanei_genesys_print_status (val);
     }
 
-    val40 = dev->read_register(REG_0x100);
+    val40 = dev->interface->read_register(REG_0x100);
 
   /* only stop action if needed */
     if (!(val40 & REG_0x100_DATAENB) && !(val40 & REG_0x100_MOTMFLG)) {
@@ -1060,7 +1060,7 @@ static void gl124_stop_action(Genesys_Device* dev)
     val = dev->reg.get8(REG_0x01);
     val &= ~REG_0x01_SCAN;
     dev->reg.set8(REG_0x01, val);
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
 
   sanei_genesys_sleep_ms(100);
 
@@ -1072,7 +1072,7 @@ static void gl124_stop_action(Genesys_Device* dev)
 	{
 	  sanei_genesys_print_status (val);
 	}
-        val40 = dev->read_register(REG_0x100);
+        val40 = dev->interface->read_register(REG_0x100);
 
       /* if scanner is in command mode, we are done */
         if (!(val40 & REG_0x100_DATAENB) && !(val40 & REG_0x100_MOTMFLG) && !(val & MOTORENB)) {
@@ -1097,7 +1097,7 @@ static void gl124_setup_scan_gpio(Genesys_Device* dev, int resolution)
 {
     DBG_HELPER(dbg);
 
-    uint8_t val = dev->read_register(REG_0x32);
+    uint8_t val = dev->interface->read_register(REG_0x32);
 
   /* LiDE 110, 210 and 220 cases */
     if(dev->model->gpio_id != GpioId::CANON_LIDE_120) {
@@ -1136,7 +1136,7 @@ static void gl124_setup_scan_gpio(Genesys_Device* dev, int resolution)
 	}
     }
   val |= 0x02;
-    dev->write_register(REG_0x32, val);
+    dev->interface->write_register(REG_0x32, val);
 }
 
 // Send the low-level scan command
@@ -1152,17 +1152,17 @@ void CommandSetGl124::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
     gl124_setup_scan_gpio(dev,dev->settings.yres);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
     // enable scan and motor
-    uint8_t val = dev->read_register(REG_0x01);
+    uint8_t val = dev->interface->read_register(REG_0x01);
     val |= REG_0x01_SCAN;
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
 
     if (start_motor) {
-        dev->write_register(REG_0x0F, 1);
+        dev->interface->write_register(REG_0x0F, 1);
     } else {
-        dev->write_register(REG_0x0F, 0);
+        dev->interface->write_register(REG_0x0F, 0);
     }
 }
 
@@ -1189,9 +1189,9 @@ void CommandSetGl124::rewind(Genesys_Device* dev) const
     DBG_HELPER(dbg);
 
     // set motor reverse
-    uint8_t byte = dev->read_register(0x02);
+    uint8_t byte = dev->interface->read_register(0x02);
     byte |= 0x04;
-    dev->write_register(0x02, byte);
+    dev->interface->write_register(0x02, byte);
 
   const auto& sensor = sanei_genesys_find_sensor_any(dev);
 
@@ -1200,14 +1200,14 @@ void CommandSetGl124::rewind(Genesys_Device* dev) const
   do
     {
         sanei_genesys_sleep_ms(100);
-        byte = dev->read_register(REG_0x100);
+        byte = dev->interface->read_register(REG_0x100);
     } while (byte & REG_0x100_MOTMFLG);
     end_scan(dev, &dev->reg, true);
 
     // restore direction
-    byte = dev->read_register(0x02);
+    byte = dev->interface->read_register(0x02);
     byte &= 0xfb;
-    dev->write_register(0x02, byte);
+    dev->interface->write_register(0x02, byte);
 }
 
 
@@ -1283,13 +1283,13 @@ void CommandSetGl124::slow_back_home(Genesys_Device* dev, bool wait_until_home)
     gl124_init_scan_regs(dev, sensor, &local_reg, session);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
   /* set up for reverse and no scan */
     r = sanei_genesys_get_address(&local_reg, REG_0x02);
     r->value |= REG_0x02_MTRREV;
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     gl124_setup_scan_gpio(dev,resolution);
 
@@ -1300,7 +1300,7 @@ void CommandSetGl124::slow_back_home(Genesys_Device* dev, bool wait_until_home)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1377,8 +1377,8 @@ static void gl124_feed(Genesys_Device* dev, unsigned int steps, int reverse)
     local_reg.set24(REG_EXPB, 0);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
-    dev->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
 
   /* set up for no scan */
     r = sanei_genesys_get_address (&local_reg, REG_0x01);
@@ -1392,7 +1392,7 @@ static void gl124_feed(Genesys_Device* dev, unsigned int steps, int reverse)
     }
 
     // send registers
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl124_start_action(dev);
@@ -1402,7 +1402,7 @@ static void gl124_feed(Genesys_Device* dev, unsigned int steps, int reverse)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1456,7 +1456,7 @@ void CommandSetGl124::search_start_position(Genesys_Device* dev) const
     gl124_init_scan_regs(dev, sensor, &local_reg, session);
 
     // send to scanner
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
   size = pixels * dev->model->search_lines;
 
@@ -1521,7 +1521,7 @@ void CommandSetGl124::init_regs_for_coarse_calibration(Genesys_Device* dev,
   DBG(DBG_info, "%s: optical sensor res: %d dpi, actual res: %d\n", __func__,
       sensor.optical_res / sensor.ccd_pixels_per_system_pixel(), dev->settings.xres);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 
@@ -1590,7 +1590,7 @@ void CommandSetGl124::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
 
   dev->scanhead_position_in_steps += dev->calib_lines + move;
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 void CommandSetGl124::wait_for_motor_stop(Genesys_Device* dev) const
@@ -1599,7 +1599,7 @@ void CommandSetGl124::wait_for_motor_stop(Genesys_Device* dev) const
     uint8_t val;
 
     val = sanei_genesys_get_status(dev);
-    uint8_t val40 = dev->read_register(REG_0x100);
+    uint8_t val40 = dev->interface->read_register(REG_0x100);
 
     if ((val & MOTORENB) == 0 && (val40 & REG_0x100_MOTMFLG) == 0)
         return;
@@ -1607,7 +1607,7 @@ void CommandSetGl124::wait_for_motor_stop(Genesys_Device* dev) const
     do {
         sanei_genesys_sleep_ms(10);
         val = sanei_genesys_get_status(dev);
-        val40 = dev->read_register(REG_0x100);
+        val40 = dev->interface->read_register(REG_0x100);
     } while ((val & MOTORENB) ||(val40 & REG_0x100_MOTMFLG));
     sanei_genesys_sleep_ms(50);
 }
@@ -1752,7 +1752,7 @@ void CommandSetGl124::send_shading_data(Genesys_Device* dev, const Genesys_Senso
           /* next shading coefficient */
           ptr+=4;
         }
-        uint8_t val = dev->read_register(0xd0+i);
+        uint8_t val = dev->interface->read_register(0xd0+i);
       addr = val * 8192 + 0x10000000;
         dev->interface->write_ahb(addr, pixels * dev->session.segment_count, buffer.data());
     }
@@ -1800,7 +1800,7 @@ static void move_to_calibration_area(Genesys_Device* dev, const Genesys_Sensor&
   std::vector<uint8_t> line(size);
 
     // write registers and scan data
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
   DBG (DBG_info, "%s: starting line reading\n", __func__);
     dev->cmd_set->begin_scan(dev, sensor, &regs, true);
@@ -1894,7 +1894,7 @@ SensorExposure CommandSetGl124::led_calibration(Genesys_Device* dev, const Genes
         regs.set24(REG_EXPB, exp[2]);
 
         // write registers and scan data
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
 
       DBG(DBG_info, "%s: starting line reading\n", __func__);
         begin_scan(dev, sensor, &regs, true);
@@ -2007,7 +2007,7 @@ void CommandSetGl124::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   int top, bottom, black_pixels, pixels;
 
     // no gain nor offset for TI AFE
-    uint8_t reg0a = dev->read_register(REG_0x0A);
+    uint8_t reg0a = dev->interface->read_register(REG_0x0A);
     if (((reg0a & REG_0x0A_SIFSEL) >> REG_0x0AS_SIFSEL) == 3) {
       return;
     }
@@ -2060,7 +2060,7 @@ void CommandSetGl124::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   dev->frontend.set_offset(2, bottom);
 
     set_fe(dev, sensor, AFE_SET);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
   DBG(DBG_info, "%s: starting first line reading\n", __func__);
     begin_scan(dev, sensor, &regs, true);
     sanei_genesys_read_data_from_scanner(dev, first_line.data(), total_size);
@@ -2081,7 +2081,7 @@ void CommandSetGl124::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   dev->frontend.set_offset(1, top);
   dev->frontend.set_offset(2, top);
     set_fe(dev, sensor, AFE_SET);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
   DBG(DBG_info, "%s: starting second line reading\n", __func__);
     begin_scan(dev, sensor, &regs, true);
     sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
@@ -2101,7 +2101,7 @@ void CommandSetGl124::offset_calibration(Genesys_Device* dev, const Genesys_Sens
 
         // scan with no move
         set_fe(dev, sensor, AFE_SET);
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
       DBG(DBG_info, "%s: starting second line reading\n", __func__);
         begin_scan(dev, sensor, &regs, true);
         sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
@@ -2157,7 +2157,7 @@ void CommandSetGl124::coarse_gain_calibration(Genesys_Device* dev, const Genesys
   int val, code, lines;
 
     // no gain nor offset for TI AFE
-    uint8_t reg0a = dev->read_register(REG_0x0A);
+    uint8_t reg0a = dev->interface->read_register(REG_0x0A);
     if (((reg0a & REG_0x0A_SIFSEL) >> REG_0x0AS_SIFSEL) == 3) {
       return;
     }
@@ -2201,7 +2201,7 @@ void CommandSetGl124::coarse_gain_calibration(Genesys_Device* dev, const Genesys
 
     sanei_genesys_set_motor_power(regs, false);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     total_size = pixels * channels * (16 / session.params.depth) * lines;
 
@@ -2307,7 +2307,7 @@ void CommandSetGl124::init_regs_for_warmup(Genesys_Device* dev, const Genesys_Se
   *total_size = num_pixels * 3 * 1;        /* colors * bytes_per_color * scan lines */
 
   sanei_genesys_set_motor_power(*reg, false);
-    dev->write_registers(*reg);
+    dev->interface->write_registers(*reg);
 }
 
 /** @brief default GPIO values
@@ -2330,13 +2330,13 @@ static void gl124_init_gpio(Genesys_Device* dev)
       idx = 1;
     }
 
-    dev->write_register(REG_0x31, gpios[idx].r31);
-    dev->write_register(REG_0x32, gpios[idx].r32);
-    dev->write_register(REG_0x33, gpios[idx].r33);
-    dev->write_register(REG_0x34, gpios[idx].r34);
-    dev->write_register(REG_0x35, gpios[idx].r35);
-    dev->write_register(REG_0x36, gpios[idx].r36);
-    dev->write_register(REG_0x38, gpios[idx].r38);
+    dev->interface->write_register(REG_0x31, gpios[idx].r31);
+    dev->interface->write_register(REG_0x32, gpios[idx].r32);
+    dev->interface->write_register(REG_0x33, gpios[idx].r33);
+    dev->interface->write_register(REG_0x34, gpios[idx].r34);
+    dev->interface->write_register(REG_0x35, gpios[idx].r35);
+    dev->interface->write_register(REG_0x36, gpios[idx].r36);
+    dev->interface->write_register(REG_0x38, gpios[idx].r38);
 }
 
 /**
@@ -2361,48 +2361,48 @@ static void gl124_init_memory_layout(Genesys_Device* dev)
   /* setup base address for shading data. */
   /* values must be multiplied by 8192=0x4000 to give address on AHB */
   /* R-Channel shading bank0 address setting for CIS */
-    dev->write_register(0xd0, layouts[idx].rd0);
+    dev->interface->write_register(0xd0, layouts[idx].rd0);
   /* G-Channel shading bank0 address setting for CIS */
-    dev->write_register(0xd1, layouts[idx].rd1);
+    dev->interface->write_register(0xd1, layouts[idx].rd1);
   /* B-Channel shading bank0 address setting for CIS */
-    dev->write_register(0xd2, layouts[idx].rd2);
+    dev->interface->write_register(0xd2, layouts[idx].rd2);
 
   /* setup base address for scanned data. */
   /* values must be multiplied by 1024*2=0x0800 to give address on AHB */
   /* R-Channel ODD image buffer 0x0124->0x92000 */
   /* size for each buffer is 0x16d*1k word */
-    dev->write_register(0xe0, layouts[idx].re0);
-    dev->write_register(0xe1, layouts[idx].re1);
+    dev->interface->write_register(0xe0, layouts[idx].re0);
+    dev->interface->write_register(0xe1, layouts[idx].re1);
   /* R-Channel ODD image buffer end-address 0x0291->0x148800 => size=0xB6800*/
-    dev->write_register(0xe2, layouts[idx].re2);
-    dev->write_register(0xe3, layouts[idx].re3);
+    dev->interface->write_register(0xe2, layouts[idx].re2);
+    dev->interface->write_register(0xe3, layouts[idx].re3);
 
   /* R-Channel EVEN image buffer 0x0292 */
-    dev->write_register(0xe4, layouts[idx].re4);
-    dev->write_register(0xe5, layouts[idx].re5);
+    dev->interface->write_register(0xe4, layouts[idx].re4);
+    dev->interface->write_register(0xe5, layouts[idx].re5);
   /* R-Channel EVEN image buffer end-address 0x03ff*/
-    dev->write_register(0xe6, layouts[idx].re6);
-    dev->write_register(0xe7, layouts[idx].re7);
+    dev->interface->write_register(0xe6, layouts[idx].re6);
+    dev->interface->write_register(0xe7, layouts[idx].re7);
 
   /* same for green, since CIS, same addresses */
-    dev->write_register(0xe8, layouts[idx].re0);
-    dev->write_register(0xe9, layouts[idx].re1);
-    dev->write_register(0xea, layouts[idx].re2);
-    dev->write_register(0xeb, layouts[idx].re3);
-    dev->write_register(0xec, layouts[idx].re4);
-    dev->write_register(0xed, layouts[idx].re5);
-    dev->write_register(0xee, layouts[idx].re6);
-    dev->write_register(0xef, layouts[idx].re7);
+    dev->interface->write_register(0xe8, layouts[idx].re0);
+    dev->interface->write_register(0xe9, layouts[idx].re1);
+    dev->interface->write_register(0xea, layouts[idx].re2);
+    dev->interface->write_register(0xeb, layouts[idx].re3);
+    dev->interface->write_register(0xec, layouts[idx].re4);
+    dev->interface->write_register(0xed, layouts[idx].re5);
+    dev->interface->write_register(0xee, layouts[idx].re6);
+    dev->interface->write_register(0xef, layouts[idx].re7);
 
 /* same for blue, since CIS, same addresses */
-    dev->write_register(0xf0, layouts[idx].re0);
-    dev->write_register(0xf1, layouts[idx].re1);
-    dev->write_register(0xf2, layouts[idx].re2);
-    dev->write_register(0xf3, layouts[idx].re3);
-    dev->write_register(0xf4, layouts[idx].re4);
-    dev->write_register(0xf5, layouts[idx].re5);
-    dev->write_register(0xf6, layouts[idx].re6);
-    dev->write_register(0xf7, layouts[idx].re7);
+    dev->interface->write_register(0xf0, layouts[idx].re0);
+    dev->interface->write_register(0xf1, layouts[idx].re1);
+    dev->interface->write_register(0xf2, layouts[idx].re2);
+    dev->interface->write_register(0xf3, layouts[idx].re3);
+    dev->interface->write_register(0xf4, layouts[idx].re4);
+    dev->interface->write_register(0xf5, layouts[idx].re5);
+    dev->interface->write_register(0xf6, layouts[idx].re6);
+    dev->interface->write_register(0xf7, layouts[idx].re7);
 }
 
 /**
@@ -2427,22 +2427,22 @@ void CommandSetGl124::asic_boot(Genesys_Device* dev, bool cold) const
 
     // reset ASIC in case of cold boot
     if (cold) {
-        dev->write_register(0x0e, 0x01);
-        dev->write_register(0x0e, 0x00);
+        dev->interface->write_register(0x0e, 0x01);
+        dev->interface->write_register(0x0e, 0x00);
     }
 
     // enable GPOE 17
-    dev->write_register(0x36, 0x01);
+    dev->interface->write_register(0x36, 0x01);
 
     // set GPIO 17
-    uint8_t val = dev->read_register(0x33);
+    uint8_t val = dev->interface->read_register(0x33);
     val |= 0x01;
-    dev->write_register(0x33, val);
+    dev->interface->write_register(0x33, val);
 
     // test CHKVER
-    val = dev->read_register(REG_0x100);
+    val = dev->interface->read_register(REG_0x100);
     if (val & REG_0x100_CHKVER) {
-        val = dev->read_register(0x00);
+        val = dev->interface->read_register(0x00);
         DBG(DBG_info, "%s: reported version for genesys chip is 0x%02x\n", __func__, val);
     }
 
@@ -2450,10 +2450,10 @@ void CommandSetGl124::asic_boot(Genesys_Device* dev, bool cold) const
   gl124_init_registers (dev);
 
     // Write initial registers
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
     // tune reg 0B
-    dev->write_register(REG_0x0B, REG_0x0B_30MHZ | REG_0x0B_ENBDRAM | REG_0x0B_64M);
+    dev->interface->write_register(REG_0x0B, REG_0x0B_30MHZ | REG_0x0B_ENBDRAM | REG_0x0B_64M);
   dev->reg.remove_reg(0x0b);
 
     //set up end access
@@ -2462,7 +2462,7 @@ void CommandSetGl124::asic_boot(Genesys_Device* dev, bool cold) const
 
   /* CIS_LINE */
     SETREG(0x08, REG_0x08_CIS_LINE);
-    dev->write_register(0x08, dev->reg.find_reg(0x08).value);
+    dev->interface->write_register(0x08, dev->reg.find_reg(0x08).value);
 
     // setup gpio
     gl124_init_gpio(dev);
@@ -2478,7 +2478,7 @@ void CommandSetGl124::update_hardware_sensors(Genesys_Scanner* s) const
      any of them.
    */
     DBG_HELPER(dbg);
-    uint8_t val = s->dev->read_register(REG_0x31);
+    uint8_t val = s->dev->interface->read_register(REG_0x31);
 
   /* TODO : for the next scanner special case,
    * add another per scanner button profile struct to avoid growing
diff --git a/backend/genesys/gl646.cpp b/backend/genesys/gl646.cpp
index 144afb331..a0c0b41be 100644
--- a/backend/genesys/gl646.cpp
+++ b/backend/genesys/gl646.cpp
@@ -123,7 +123,7 @@ print_status (uint8_t val)
 static void gl646_start_motor(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x01);
+    dev->interface->write_register(0x0f, 0x01);
 }
 
 
@@ -134,7 +134,7 @@ static void gl646_start_motor(Genesys_Device* dev)
 static void gl646_stop_motor(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x00);
+    dev->interface->write_register(0x0f, 0x00);
 }
 
 /**
@@ -890,7 +890,7 @@ static void gl646_wm_hp3670(Genesys_Device* dev, const Genesys_Sensor& sensor, u
     case AFE_INIT:
         dev->interface->write_fe_register(0x04, 0x80);
       sanei_genesys_sleep_ms(200);
-    dev->write_register(0x50, 0x00);
+    dev->interface->write_register(0x50, 0x00);
       dev->frontend = dev->frontend_initial;
         dev->interface->write_fe_register(0x01, dev->frontend.regs.get_value(0x01));
         dev->interface->write_fe_register(0x02, dev->frontend.regs.get_value(0x02));
@@ -1111,7 +1111,7 @@ void CommandSetGl646::set_powersaving(Genesys_Device* dev, int delay /* in minut
   local_reg.find_reg(0x38).value = exposure_time / 256;
   local_reg.find_reg(0x39).value = exposure_time & 255;
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 }
 
 
@@ -1203,7 +1203,7 @@ void CommandSetGl646::load_document(Genesys_Device* dev) const
     // wait e1 status to become e0
     gl646_send_slope_table(dev, 1, slope_table, 50);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     gl646_start_motor(dev);
 
@@ -1228,7 +1228,7 @@ void CommandSetGl646::load_document(Genesys_Device* dev) const
   regs.set8(0x02, 0x71);
   regs.set8(0x3f, 1);
   regs.set8(0x6b, 8);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 /**
@@ -1329,7 +1329,7 @@ void CommandSetGl646::eject_document(Genesys_Device* dev) const
     }
 
     // there is a document inserted, eject it
-    dev->write_register(0x01, 0xb0);
+    dev->interface->write_register(0x01, 0xb0);
 
   /* wait for motor to stop */
   do
@@ -1374,7 +1374,7 @@ void CommandSetGl646::eject_document(Genesys_Device* dev) const
     // wait c1 status to become c8 : HOMESNR and ~MOTFLAG
     gl646_send_slope_table(dev, 1, slope_table, 60);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     gl646_start_motor(dev);
 
@@ -1414,7 +1414,7 @@ void CommandSetGl646::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
         local_reg.init_reg(0x0f, 0x00); // do not start motor yet
     }
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 }
 
 
@@ -1443,7 +1443,7 @@ static void end_scan_impl(Genesys_Device* dev, Genesys_Register_Set* reg, bool c
     val = reg->get8(0x01);
     val &= ~REG_0x01_SCAN;
     reg->set8(0x01, val);
-    dev->write_register(0x01, val);
+    dev->interface->write_register(0x01, val);
 
   /* for sheetfed scanners, we may have to eject document */
     if (dev->model->is_sheetfed) {
@@ -1602,7 +1602,7 @@ void CommandSetGl646::slow_back_home(Genesys_Device* dev, bool wait_until_home)
 
   /* write scan registers */
     try {
-        dev->write_registers(dev->reg);
+        dev->interface->write_registers(dev->reg);
     } catch (...) {
         DBG(DBG_error, "%s: failed to bulk write registers\n", __func__);
     }
@@ -2710,7 +2710,7 @@ void CommandSetGl646::init_regs_for_warmup(Genesys_Device* dev, const Genesys_Se
 
     // now registers are ok, write them to scanner
     gl646_set_fe(dev, local_sensor, AFE_SET, settings.xres);
-    dev->write_registers(*local_reg);
+    dev->interface->write_registers(*local_reg);
 }
 
 
@@ -2748,7 +2748,7 @@ static void gl646_repark_head(Genesys_Device* dev)
   /* TODO seems wrong ... no effective scan */
     dev->reg.find_reg(0x01).value &= ~REG_0x01_SCAN;
 
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
     // start scan
     dev->cmd_set->begin_scan(dev, sensor, &dev->reg, true);
@@ -2822,11 +2822,11 @@ void CommandSetGl646::init(Genesys_Device* dev) const
         dev->usb_dev.control_msg(REQUEST_TYPE_OUT, REQUEST_REGISTER, VALUE_INIT, INDEX, 1, &val);
 
         // ASIC reset
-        dev->write_register(0x0e, 0x00);
+        dev->interface->write_register(0x0e, 0x00);
       sanei_genesys_sleep_ms(100);
 
         // Write initial registers
-        dev->write_registers(dev->reg);
+        dev->interface->write_registers(dev->reg);
 
         // send gamma tables if needed
         dev->cmd_set->send_gamma_table(dev, sensor);
@@ -2840,8 +2840,8 @@ void CommandSetGl646::init(Genesys_Device* dev) const
 
   /* GPO enabling for XP200 */
     if (dev->model->sensor_id == SensorId::CIS_XP200) {
-        dev->write_register(0x68, dev->gpo.regs.get_value(0x68));
-        dev->write_register(0x69, dev->gpo.regs.get_value(0x69));
+        dev->interface->write_register(0x68, dev->gpo.regs.get_value(0x68));
+        dev->interface->write_register(0x69, dev->gpo.regs.get_value(0x69));
 
         // enable GPIO
         gl646_gpio_output_enable(dev->usb_dev, 6);
@@ -2852,9 +2852,9 @@ void CommandSetGl646::init(Genesys_Device* dev) const
         // clear GPIO enable
         gl646_gpio_output_enable(dev->usb_dev, 0);
 
-        dev->write_register(0x66, 0x10);
-        dev->write_register(0x66, 0x00);
-        dev->write_register(0x66, 0x10);
+        dev->interface->write_register(0x66, 0x10);
+        dev->interface->write_register(0x66, 0x00);
+        dev->interface->write_register(0x66, 0x10);
     }
 
   /* MD6471/G2410 and XP200 read/write data from an undocumented memory area which
@@ -3009,7 +3009,7 @@ static void simple_scan(Genesys_Device* dev, const Genesys_Sensor& sensor,
     }
 
     // write scan registers
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
     // starts scan
     dev->cmd_set->begin_scan(dev, sensor, &dev->reg, move);
diff --git a/backend/genesys/gl841.cpp b/backend/genesys/gl841.cpp
index b3dabcbb0..753cf1d41 100644
--- a/backend/genesys/gl841.cpp
+++ b/backend/genesys/gl841.cpp
@@ -66,10 +66,10 @@ static void gl841_set_buffer_address_gamma(Genesys_Device* dev, uint32_t addr)
 
   addr = addr >> 4;
 
-    dev->write_register(0x5c, (addr & 0xff));
+    dev->interface->write_register(0x5c, (addr & 0xff));
 
   addr = addr >> 8;
-    dev->write_register(0x5b, (addr & 0xff));
+    dev->interface->write_register(0x5b, (addr & 0xff));
 }
 
 bool CommandSetGl841::get_gain4_bit(Genesys_Register_Set* regs) const
@@ -340,31 +340,31 @@ gl841_init_lide80 (Genesys_Device * dev)
     }
 
     // specific scanner settings, clock and gpio first
-    val = dev->read_register(REG_0x6B);
-    dev->write_register(REG_0x6B, 0x0c);
-    dev->write_register(0x06, 0x10);
-    dev->write_register(REG_0x6E, 0x6d);
-    dev->write_register(REG_0x6F, 0x80);
-    dev->write_register(REG_0x6B, 0x0e);
-    val = dev->read_register(REG_0x6C);
-    dev->write_register(REG_0x6C, 0x00);
-    val = dev->read_register(REG_0x6D);
-    dev->write_register(REG_0x6D, 0x8f);
-    val = dev->read_register(REG_0x6B);
-    dev->write_register(REG_0x6B, 0x0e);
-    val = dev->read_register(REG_0x6B);
-    dev->write_register(REG_0x6B, 0x0e);
-    val = dev->read_register(REG_0x6B);
-    dev->write_register(REG_0x6B, 0x0a);
-    val = dev->read_register(REG_0x6B);
-    dev->write_register(REG_0x6B, 0x02);
-    val = dev->read_register(REG_0x6B);
-    dev->write_register(REG_0x6B, 0x06);
+    val = dev->interface->read_register(REG_0x6B);
+    dev->interface->write_register(REG_0x6B, 0x0c);
+    dev->interface->write_register(0x06, 0x10);
+    dev->interface->write_register(REG_0x6E, 0x6d);
+    dev->interface->write_register(REG_0x6F, 0x80);
+    dev->interface->write_register(REG_0x6B, 0x0e);
+    val = dev->interface->read_register(REG_0x6C);
+    dev->interface->write_register(REG_0x6C, 0x00);
+    val = dev->interface->read_register(REG_0x6D);
+    dev->interface->write_register(REG_0x6D, 0x8f);
+    val = dev->interface->read_register(REG_0x6B);
+    dev->interface->write_register(REG_0x6B, 0x0e);
+    val = dev->interface->read_register(REG_0x6B);
+    dev->interface->write_register(REG_0x6B, 0x0e);
+    val = dev->interface->read_register(REG_0x6B);
+    dev->interface->write_register(REG_0x6B, 0x0a);
+    val = dev->interface->read_register(REG_0x6B);
+    dev->interface->write_register(REG_0x6B, 0x02);
+    val = dev->interface->read_register(REG_0x6B);
+    dev->interface->write_register(REG_0x6B, 0x06);
 
     (void) val; // FIXME: we don't use the information read from registers
 
     dev->interface->write_0x8c(0x10, 0x94);
-    dev->write_register(0x09, 0x10);
+    dev->interface->write_register(0x09, 0x10);
 
   // FIXME: the following code originally changed 0x6b, but due to bug the 0x6c register was
   // effectively changed. The current behavior matches the old code, but should probably be fixed.
@@ -812,12 +812,12 @@ uint8_t *table;
           default:
             table=tdefault;
         }
-        dev->write_register(0x66, 0x00);
-        dev->write_register(0x5b, 0x0c);
-        dev->write_register(0x5c, 0x00);
+        dev->interface->write_register(0x66, 0x00);
+        dev->interface->write_register(0x5b, 0x0c);
+        dev->interface->write_register(0x5c, 0x00);
         dev->interface->bulk_write_data(0x28, table, 128);
-        dev->write_register(0x5b, 0x00);
-        dev->write_register(0x5c, 0x00);
+        dev->interface->write_register(0x5b, 0x00);
+        dev->interface->write_register(0x5c, 0x00);
     }
 }
 
@@ -1715,33 +1715,33 @@ void CommandSetGl841::save_power(Genesys_Device* dev, bool enable) const
 /* final state: GPIO8 disabled, GPIO9 enabled, GPIO17 disabled,
    GPIO18 disabled*/
 
-            uint8_t val = dev->read_register(REG_0x6D);
-            dev->write_register(REG_0x6D, val | 0x80);
+            uint8_t val = dev->interface->read_register(REG_0x6D);
+            dev->interface->write_register(REG_0x6D, val | 0x80);
 
             sanei_genesys_sleep_ms(1);
 
 	    /*enable GPIO9*/
-            val = dev->read_register(REG_0x6C);
-            dev->write_register(REG_0x6C, val | 0x01);
+            val = dev->interface->read_register(REG_0x6C);
+            dev->interface->write_register(REG_0x6C, val | 0x01);
 
 	    /*disable GPO17*/
-            val = dev->read_register(REG_0x6B);
-            dev->write_register(REG_0x6B, val & ~REG_0x6B_GPO17);
+            val = dev->interface->read_register(REG_0x6B);
+            dev->interface->write_register(REG_0x6B, val & ~REG_0x6B_GPO17);
 
 	    /*disable GPO18*/
-            val = dev->read_register(REG_0x6B);
-            dev->write_register(REG_0x6B, val & ~REG_0x6B_GPO18);
+            val = dev->interface->read_register(REG_0x6B);
+            dev->interface->write_register(REG_0x6B, val & ~REG_0x6B_GPO18);
 
             sanei_genesys_sleep_ms(1);
 
-            val = dev->read_register(REG_0x6D);
-            dev->write_register(REG_0x6D, val & ~0x80);
+            val = dev->interface->read_register(REG_0x6D);
+            dev->interface->write_register(REG_0x6D, val & ~0x80);
 
 	}
     if (dev->model->gpio_id == GpioId::DP685)
 	  {
-            uint8_t val = dev->read_register(REG_0x6B);
-            dev->write_register(REG_0x6B, val & ~REG_0x6B_GPO17);
+            uint8_t val = dev->interface->read_register(REG_0x6B);
+            dev->interface->write_register(REG_0x6B, val & ~REG_0x6B_GPO17);
             dev->reg.find_reg(0x6b).value &= ~REG_0x6B_GPO17;
             dev->calib_reg.find_reg(0x6b).value &= ~REG_0x6B_GPO17;
 	  }
@@ -1758,28 +1758,28 @@ void CommandSetGl841::save_power(Genesys_Device* dev, bool enable) const
 /* final state: GPIO8 enabled, GPIO9 disabled, GPIO17 enabled,
    GPIO18 enabled*/
 
-            uint8_t val = dev->read_register(REG_0x6D);
-            dev->write_register(REG_0x6D, val | 0x80);
+            uint8_t val = dev->interface->read_register(REG_0x6D);
+            dev->interface->write_register(REG_0x6D, val | 0x80);
 
             sanei_genesys_sleep_ms(10);
 
 	    /*disable GPIO9*/
-            val = dev->read_register(REG_0x6C);
-            dev->write_register(REG_0x6C, val & ~0x01);
+            val = dev->interface->read_register(REG_0x6C);
+            dev->interface->write_register(REG_0x6C, val & ~0x01);
 
 	    /*enable GPIO10*/
-            val = dev->read_register(REG_0x6C);
-            dev->write_register(REG_0x6C, val | 0x02);
+            val = dev->interface->read_register(REG_0x6C);
+            dev->interface->write_register(REG_0x6C, val | 0x02);
 
 	    /*enable GPO17*/
-            val = dev->read_register(REG_0x6B);
-            dev->write_register(REG_0x6B, val | REG_0x6B_GPO17);
+            val = dev->interface->read_register(REG_0x6B);
+            dev->interface->write_register(REG_0x6B, val | REG_0x6B_GPO17);
             dev->reg.find_reg(0x6b).value |= REG_0x6B_GPO17;
             dev->calib_reg.find_reg(0x6b).value |= REG_0x6B_GPO17;
 
 	    /*enable GPO18*/
-            val = dev->read_register(REG_0x6B);
-            dev->write_register(REG_0x6B, val | REG_0x6B_GPO18);
+            val = dev->interface->read_register(REG_0x6B);
+            dev->interface->write_register(REG_0x6B, val | REG_0x6B_GPO18);
             dev->reg.find_reg(0x6b).value |= REG_0x6B_GPO18;
             dev->calib_reg.find_reg(0x6b).value |= REG_0x6B_GPO18;
 
@@ -1787,8 +1787,8 @@ void CommandSetGl841::save_power(Genesys_Device* dev, bool enable) const
     if (dev->model->gpio_id == GpioId::DP665
             || dev->model->gpio_id == GpioId::DP685)
 	  {
-            uint8_t val = dev->read_register(REG_0x6B);
-            dev->write_register(REG_0x6B, val | REG_0x6B_GPO17);
+            uint8_t val = dev->interface->read_register(REG_0x6B);
+            dev->interface->write_register(REG_0x6B, val | REG_0x6B_GPO17);
             dev->reg.find_reg(0x6b).value |= REG_0x6B_GPO17;
             dev->calib_reg.find_reg(0x6b).value |= REG_0x6B_GPO17;
 	  }
@@ -1857,13 +1857,13 @@ void CommandSetGl841::set_powersaving(Genesys_Device* dev, int delay /* in minut
   local_reg.set8(0x38, exposure_time >> 8);
   local_reg.set8(0x39, exposure_time & 255);	/* lowbyte */
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 }
 
 static void gl841_start_action(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x01);
+    dev->interface->write_register(0x0f, 0x01);
 }
 
 static void gl841_stop_action(Genesys_Device* dev)
@@ -1879,7 +1879,7 @@ static void gl841_stop_action(Genesys_Device* dev)
       sanei_genesys_print_status (val);
     }
 
-    uint8_t val40 = dev->read_register(0x40);
+    uint8_t val40 = dev->interface->read_register(0x40);
 
   /* only stop action if needed */
     if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG)) {
@@ -1892,7 +1892,7 @@ static void gl841_stop_action(Genesys_Device* dev)
   gl841_init_optical_regs_off(&local_reg);
 
     gl841_init_motor_regs_off(&local_reg,0);
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
   /* looks like writing the right registers to zero is enough to get the chip
      out of scan mode into command mode, actually triggering(writing to
@@ -1900,7 +1900,7 @@ static void gl841_stop_action(Genesys_Device* dev)
 
   loop = 10;
     while (loop > 0) {
-        val40 = dev->read_register(0x40);
+        val40 = dev->interface->read_register(0x40);
         if (DBG_LEVEL >= DBG_io) {
             sanei_genesys_print_status(val);
         }
@@ -1921,7 +1921,7 @@ static bool gl841_get_paper_sensor(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
 
-    uint8_t val = dev->read_register(REG_0x6D);
+    uint8_t val = dev->interface->read_register(REG_0x6D);
 
     return (val & 0x1) == 0;
 }
@@ -1955,7 +1955,7 @@ void CommandSetGl841::eject_document(Genesys_Device* dev) const
   gl841_init_motor_regs(dev, sensor, &local_reg,
 			65536,MOTOR_ACTION_FEED,0);
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl841_start_action(dev);
@@ -1964,7 +1964,7 @@ void CommandSetGl841::eject_document(Genesys_Device* dev) const
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -2131,9 +2131,9 @@ void CommandSetGl841::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
   uint8_t val;
 
     if (dev->model->gpio_id == GpioId::CANON_LIDE_80) {
-        val = dev->read_register(REG_0x6B);
+        val = dev->interface->read_register(REG_0x6B);
         val = REG_0x6B_GPO18;
-        dev->write_register(REG_0x6B, val);
+        dev->interface->write_register(REG_0x6B, val);
     }
 
     if (dev->model->sensor_id != SensorId::CCD_PLUSTEK_OPTICPRO_3600) {
@@ -2153,7 +2153,7 @@ void CommandSetGl841::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
         local_reg.init_reg(0x0f, 0x00);
     }
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 }
 
 
@@ -2187,7 +2187,7 @@ static void gl841_feed(Genesys_Device* dev, int steps)
 
   gl841_init_motor_regs(dev, sensor, &local_reg, steps,MOTOR_ACTION_FEED,0);
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl841_start_action(dev);
@@ -2196,7 +2196,7 @@ static void gl841_feed(Genesys_Device* dev, int steps)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -2238,14 +2238,14 @@ void CommandSetGl841::slow_back_home(Genesys_Device* dev, bool wait_until_home)
     // reset gpio pin
     uint8_t val;
     if (dev->model->gpio_id == GpioId::CANON_LIDE_35) {
-        val = dev->read_register(REG_0x6C);
+        val = dev->interface->read_register(REG_0x6C);
         val = dev->gpo.regs.get_value(0x6c);
-        dev->write_register(REG_0x6C, val);
+        dev->interface->write_register(REG_0x6C, val);
     }
     if (dev->model->gpio_id == GpioId::CANON_LIDE_80) {
-        val = dev->read_register(REG_0x6B);
+        val = dev->interface->read_register(REG_0x6B);
         val = REG_0x6B_GPO18 | REG_0x6B_GPO17;
-        dev->write_register(REG_0x6B, val);
+        dev->interface->write_register(REG_0x6B, val);
     }
     dev->cmd_set->save_power(dev, false);
 
@@ -2278,7 +2278,7 @@ void CommandSetGl841::slow_back_home(Genesys_Device* dev, bool wait_until_home)
   /* end previous scan if any */
     r = sanei_genesys_get_address(&dev->reg, REG_0x01);
     r->value &= ~REG_0x01_SCAN;
-    dev->write_register(REG_0x01, r->value);
+    dev->interface->write_register(REG_0x01, r->value);
 
   /* if motor is on, stop current action */
     if (val & REG_0x41_MOTORENB) {
@@ -2297,7 +2297,7 @@ void CommandSetGl841::slow_back_home(Genesys_Device* dev, bool wait_until_home)
     r = sanei_genesys_get_address(&local_reg, REG_0x01);
     r->value &= ~REG_0x01_SCAN;
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl841_start_action(dev);
@@ -2306,7 +2306,7 @@ void CommandSetGl841::slow_back_home(Genesys_Device* dev, bool wait_until_home)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -2377,7 +2377,7 @@ void CommandSetGl841::search_start_position(Genesys_Device* dev) const
     gl841_init_scan_regs(dev, sensor, &local_reg, session);
 
     // send to scanner
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
   size = pixels * dev->model->search_lines;
 
@@ -2439,7 +2439,7 @@ void CommandSetGl841::init_regs_for_coarse_calibration(Genesys_Device* dev,
   DBG(DBG_info, "%s: optical sensor res: %d dpi, actual res: %d\n", __func__,
       sensor.optical_res / sensor.ccd_pixels_per_system_pixel(), dev->settings.xres);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
 /*  if (DBG_LEVEL >= DBG_info)
     sanei_gl841_print_registers (regs);*/
@@ -2510,7 +2510,7 @@ void CommandSetGl841::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
 
   dev->scanhead_position_in_steps += dev->calib_lines + starty;
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 // set up registers for the actual scan
@@ -2685,7 +2685,7 @@ SensorExposure CommandSetGl841::led_calibration(Genesys_Device* dev, const Genes
 
     gl841_init_scan_regs(dev, calib_sensor_base, &regs, session);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
 
   total_size = num_pixels * channels * 2 * 1;	/* colors * bytes_per_color * scan lines */
@@ -2719,14 +2719,14 @@ SensorExposure CommandSetGl841::led_calibration(Genesys_Device* dev, const Genes
         calib_sensor.exposure.blue = exp[2];
 
         sanei_genesys_set_exposure(regs, calib_sensor.exposure);
-        dev->write_register(0x10, (calib_sensor.exposure.red >> 8) & 0xff);
-        dev->write_register(0x11, calib_sensor.exposure.red & 0xff);
-        dev->write_register(0x12, (calib_sensor.exposure.green >> 8) & 0xff);
-        dev->write_register(0x13, calib_sensor.exposure.green & 0xff);
-        dev->write_register(0x14, (calib_sensor.exposure.blue >> 8) & 0xff);
-        dev->write_register(0x15, calib_sensor.exposure.blue & 0xff);
+        dev->interface->write_register(0x10, (calib_sensor.exposure.red >> 8) & 0xff);
+        dev->interface->write_register(0x11, calib_sensor.exposure.red & 0xff);
+        dev->interface->write_register(0x12, (calib_sensor.exposure.green >> 8) & 0xff);
+        dev->interface->write_register(0x13, calib_sensor.exposure.green & 0xff);
+        dev->interface->write_register(0x14, (calib_sensor.exposure.blue >> 8) & 0xff);
+        dev->interface->write_register(0x15, calib_sensor.exposure.blue & 0xff);
 
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
 
       DBG(DBG_info, "%s: starting line reading\n", __func__);
         dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
@@ -2910,7 +2910,7 @@ static void ad_fe_offset_calibration(Genesys_Device* dev, const Genesys_Sensor&
 
       /* scan line */
       DBG(DBG_info, "%s: starting line reading\n", __func__);
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
       dev->cmd_set->set_fe(dev, calib_sensor, AFE_SET);
         dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
       sanei_genesys_read_data_from_scanner(dev, line.data(), total_size);
@@ -3050,7 +3050,7 @@ void CommandSetGl841::offset_calibration(Genesys_Device* dev, const Genesys_Sens
     bool acceptable = false;
   do {
 
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
 
       for (j=0; j < channels; j++) {
 	  off[j] = (offh[j]+offl[j])/2;
@@ -3167,7 +3167,7 @@ void CommandSetGl841::offset_calibration(Genesys_Device* dev, const Genesys_Sens
         dev->cmd_set->set_fe(dev, calib_sensor, AFE_SET);
 
       DBG(DBG_info, "%s: starting second line reading\n", __func__);
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
         dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
         sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
 
@@ -3377,7 +3377,7 @@ void CommandSetGl841::coarse_gain_calibration(Genesys_Device* dev, const Genesys
 
     gl841_init_scan_regs(dev, calib_sensor, &regs, session);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
   total_size = num_pixels * channels * 2 * lines;	/* colors * bytes_per_color * scan lines */
 
@@ -3526,7 +3526,7 @@ void CommandSetGl841::init_regs_for_warmup(Genesys_Device* dev, const Genesys_Se
 
   *total_size = num_pixels * 3 * 2 * 1;	/* colors * bytes_per_color * scan lines */
 
-    dev->write_registers(*local_reg);
+    dev->interface->write_registers(*local_reg);
 }
 
 
@@ -3575,14 +3575,14 @@ void CommandSetGl841::init(Genesys_Device* dev) const
   dev->settings.color_filter = ColorFilter::RED;
 
     // ASIC reset
-    dev->write_register(0x0e, 0x01);
-    dev->write_register(0x0e, 0x00);
+    dev->interface->write_register(0x0e, 0x01);
+    dev->interface->write_register(0x0e, 0x00);
 
   /* Set default values for registers */
   gl841_init_registers (dev);
 
     // Write initial registers
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
   const auto& sensor = sanei_genesys_find_sensor_any(dev);
 
@@ -3641,7 +3641,7 @@ void CommandSetGl841::init(Genesys_Device* dev) const
 
     gl841_init_scan_regs(dev, calib_sensor, &regs, session);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     size = num_pixels * 3 * 2 * 1; // colors * bytes_per_color * scan lines
 
@@ -3677,7 +3677,7 @@ void CommandSetGl841::update_hardware_sensors(Genesys_Scanner* s) const
     if (s->dev->model->gpio_id == GpioId::CANON_LIDE_35
         || s->dev->model->gpio_id == GpioId::CANON_LIDE_80)
     {
-        val = s->dev->read_register(REG_0x6D);
+        val = s->dev->interface->read_register(REG_0x6D);
         s->buttons[BUTTON_SCAN_SW].write((val & 0x01) == 0);
         s->buttons[BUTTON_FILE_SW].write((val & 0x02) == 0);
         s->buttons[BUTTON_EMAIL_SW].write((val & 0x04) == 0);
@@ -3688,7 +3688,7 @@ void CommandSetGl841::update_hardware_sensors(Genesys_Scanner* s) const
         s->dev->model->gpio_id == GpioId::DP665 ||
         s->dev->model->gpio_id == GpioId::DP685)
     {
-        val = s->dev->read_register(REG_0x6D);
+        val = s->dev->interface->read_register(REG_0x6D);
 
         s->buttons[BUTTON_PAGE_LOADED_SW].write((val & 0x01) == 0);
         s->buttons[BUTTON_SCAN_SW].write((val & 0x02) == 0);
@@ -3774,7 +3774,7 @@ void CommandSetGl841::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
         r->value |= 4;
     }
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     dev->cmd_set->begin_scan(dev, sensor, &local_reg, true);
 
@@ -3799,7 +3799,7 @@ void CommandSetGl841::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
   found = 0;
   while (pass < length && !found)
     {
-        dev->write_registers(local_reg);
+        dev->interface->write_registers(local_reg);
 
         //now start scan
         dev->cmd_set->begin_scan(dev, sensor, &local_reg, true);
diff --git a/backend/genesys/gl843.cpp b/backend/genesys/gl843.cpp
index 0b67f87b7..489c382ba 100644
--- a/backend/genesys/gl843.cpp
+++ b/backend/genesys/gl843.cpp
@@ -57,17 +57,17 @@ static void gl843_set_buffer_address(Genesys_Device* dev, uint32_t addr)
 {
     DBG_HELPER_ARGS(dbg, "setting address to 0x%05x", addr & 0xffff);
 
-    dev->write_register(0x5b, ((addr >> 8) & 0xff));
-    dev->write_register(0x5c, (addr & 0xff));
+    dev->interface->write_register(0x5b, ((addr >> 8) & 0xff));
+    dev->interface->write_register(0x5c, (addr & 0xff));
 }
 
 static void gl843_set_ram_address(Genesys_Device* dev, uint32_t addr)
 {
     DBG_HELPER_ARGS(dbg, "setting address to 0x%05x", addr & 0x1fffff);
 
-    dev->write_register(0x29, ((addr >> 16) & 0x1f));
-    dev->write_register(0x2a, ((addr >> 8) & 0xff));
-    dev->write_register(0x2b, (addr & 0xff));
+    dev->interface->write_register(0x29, ((addr >> 16) & 0x1f));
+    dev->interface->write_register(0x2a, ((addr >> 8) & 0xff));
+    dev->interface->write_register(0x2b, (addr & 0xff));
 }
 
 /**
@@ -775,7 +775,7 @@ void CommandSetGl843::set_fe(Genesys_Device* dev, const Genesys_Sensor& sensor,
 
     // check analog frontend type
     // FIXME: looks like we write to that register with initial data
-    uint8_t fe_type = dev->read_register(REG_0x04) & REG_0x04_FESET;
+    uint8_t fe_type = dev->interface->read_register(REG_0x04) & REG_0x04_FESET;
     if (fe_type == 2) {
         gl843_set_ad_fe(dev);
         return;
@@ -1328,13 +1328,13 @@ void CommandSetGl843::save_power(Genesys_Device* dev, bool enable) const
 
     // switch KV-SS080 lamp off
     if (dev->model->gpio_id == GpioId::KVSS080) {
-        uint8_t val = dev->read_register(REG_0x6C);
+        uint8_t val = dev->interface->read_register(REG_0x6C);
         if (enable) {
             val &= 0xef;
         } else {
             val |= 0x10;
         }
-        dev->write_register(REG_0x6C, val);
+        dev->interface->write_register(REG_0x6C, val);
     }
 }
 
@@ -1347,7 +1347,7 @@ void CommandSetGl843::set_powersaving(Genesys_Device* dev, int delay /* in minut
 static void gl843_start_action(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x01);
+    dev->interface->write_register(0x0f, 0x01);
 }
 
 static void gl843_stop_action_no_move(Genesys_Device* dev, Genesys_Register_Set* reg)
@@ -1356,7 +1356,7 @@ static void gl843_stop_action_no_move(Genesys_Device* dev, Genesys_Register_Set*
     uint8_t val = reg->get8(REG_0x01);
     val &= ~REG_0x01_SCAN;
     reg->set8(REG_0x01, val);
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
     sanei_genesys_sleep_ms(100);
 }
 
@@ -1372,7 +1372,7 @@ static void gl843_stop_action(Genesys_Device* dev)
       sanei_genesys_print_status (val);
     }
 
-    uint8_t val40 = dev->read_register(REG_0x40);
+    uint8_t val40 = dev->interface->read_register(REG_0x40);
 
   /* only stop action if needed */
     if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG))
@@ -1385,7 +1385,7 @@ static void gl843_stop_action(Genesys_Device* dev)
     val = dev->reg.get8(REG_0x01);
     val &= ~REG_0x01_SCAN;
     dev->reg.set8(REG_0x01, val);
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
 
   sanei_genesys_sleep_ms(100);
 
@@ -1397,7 +1397,7 @@ static void gl843_stop_action(Genesys_Device* dev)
 	{
 	  sanei_genesys_print_status (val);
 	}
-        val40 = dev->read_register(0x40);
+        val40 = dev->interface->read_register(0x40);
 
       /* if scanner is in command mode, we are done */
         if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG)
@@ -1417,7 +1417,7 @@ static bool gl843_get_paper_sensor(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
 
-    uint8_t val = dev->read_register(REG_0x6D);
+    uint8_t val = dev->interface->read_register(REG_0x6D);
 
     return (val & 0x1) == 0;
 }
@@ -1492,87 +1492,87 @@ static void gl843_set_xpa_motor_power(Genesys_Device* dev, bool set)
     if (dev->model->model_id == ModelId::CANON_8400F) {
 
         if (set) {
-            val = dev->read_register(0x6c);
+            val = dev->interface->read_register(0x6c);
             val &= ~(REG_0x6C_GPIO16 | REG_0x6C_GPIO13);
             if (dev->session.output_resolution >= 2400) {
                 val &= ~REG_0x6C_GPIO10;
             }
-            dev->write_register(0x6c, val);
+            dev->interface->write_register(0x6c, val);
 
-            val = dev->read_register(0xa9);
+            val = dev->interface->read_register(0xa9);
             val |= REG_0xA9_GPO30;
             val &= ~REG_0xA9_GPO29;
-            dev->write_register(0xa9, val);
+            dev->interface->write_register(0xa9, val);
         } else {
-            val = dev->read_register(0x6c);
+            val = dev->interface->read_register(0x6c);
             val |= REG_0x6C_GPIO16 | REG_0x6C_GPIO13;
-            dev->write_register(0x6c, val);
+            dev->interface->write_register(0x6c, val);
 
-            val = dev->read_register(0xa9);
+            val = dev->interface->read_register(0xa9);
             val &= ~REG_0xA9_GPO30;
             val |= REG_0xA9_GPO29;
-            dev->write_register(0xa9, val);
+            dev->interface->write_register(0xa9, val);
         }
     } else if (dev->model->model_id == ModelId::CANON_8600F) {
         if (set) {
-            val = dev->read_register(REG_0x6C);
+            val = dev->interface->read_register(REG_0x6C);
             val &= ~REG_0x6C_GPIO14;
             if (dev->session.output_resolution >= 2400) {
                 val |= REG_0x6C_GPIO10;
             }
-            dev->write_register(REG_0x6C, val);
+            dev->interface->write_register(REG_0x6C, val);
 
-            val = dev->read_register(REG_0xA6);
+            val = dev->interface->read_register(REG_0xA6);
             val |= REG_0xA6_GPIO17;
             val &= ~REG_0xA6_GPIO23;
-            dev->write_register(REG_0xA6, val);
+            dev->interface->write_register(REG_0xA6, val);
         } else {
-            val = dev->read_register(REG_0x6C);
+            val = dev->interface->read_register(REG_0x6C);
             val |= REG_0x6C_GPIO14;
             val &= ~REG_0x6C_GPIO10;
-            dev->write_register(REG_0x6C, val);
+            dev->interface->write_register(REG_0x6C, val);
 
-            val = dev->read_register(REG_0xA6);
+            val = dev->interface->read_register(REG_0xA6);
             val &= ~REG_0xA6_GPIO17;
             val &= ~REG_0xA6_GPIO23;
-            dev->write_register(REG_0xA6, val);
+            dev->interface->write_register(REG_0xA6, val);
         }
     } else if (dev->model->model_id == ModelId::HP_SCANJET_G4050) {
         if (set) {
             // set MULTFILM et GPOADF
-            val = dev->read_register(REG_0x6B);
+            val = dev->interface->read_register(REG_0x6B);
             val |=REG_0x6B_MULTFILM|REG_0x6B_GPOADF;
-            dev->write_register(REG_0x6B, val);
+            dev->interface->write_register(REG_0x6B, val);
 
-            val = dev->read_register(REG_0x6C);
+            val = dev->interface->read_register(REG_0x6C);
             val &= ~REG_0x6C_GPIO15;
-            dev->write_register(REG_0x6C, val);
+            dev->interface->write_register(REG_0x6C, val);
 
             /* Motor power ? No move at all without this one */
-            val = dev->read_register(REG_0xA6);
+            val = dev->interface->read_register(REG_0xA6);
             val |= REG_0xA6_GPIO20;
-            dev->write_register(REG_0xA6, val);
+            dev->interface->write_register(REG_0xA6, val);
 
-            val = dev->read_register(REG_0xA8);
+            val = dev->interface->read_register(REG_0xA8);
             val &= ~REG_0xA8_GPO27;
-            dev->write_register(REG_0xA8, val);
+            dev->interface->write_register(REG_0xA8, val);
 
-            val = dev->read_register(REG_0xA9);
+            val = dev->interface->read_register(REG_0xA9);
             val |= REG_0xA9_GPO32|REG_0xA9_GPO31;
-            dev->write_register(REG_0xA9, val);
+            dev->interface->write_register(REG_0xA9, val);
         } else {
             // unset GPOADF
-            val = dev->read_register(REG_0x6B);
+            val = dev->interface->read_register(REG_0x6B);
             val &= ~REG_0x6B_GPOADF;
-            dev->write_register(REG_0x6B, val);
+            dev->interface->write_register(REG_0x6B, val);
 
-            val = dev->read_register(REG_0xA8);
+            val = dev->interface->read_register(REG_0xA8);
             val |= REG_0xA8_GPO27;
-            dev->write_register(REG_0xA8, val);
+            dev->interface->write_register(REG_0xA8, val);
 
-            val = dev->read_register(REG_0xA9);
+            val = dev->interface->read_register(REG_0xA9);
             val &= ~REG_0xA9_GPO31;
-            dev->write_register(REG_0xA9, val);
+            dev->interface->write_register(REG_0xA9, val);
         }
     }
 }
@@ -1681,21 +1681,21 @@ void CommandSetGl843::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
     switch(dev->model->gpio_id) {
       /* KV case */
         case GpioId::KVSS080:
-            dev->write_register(REG_0xA9, 0x00);
-            dev->write_register(REG_0xA6, 0xf6);
+            dev->interface->write_register(REG_0xA9, 0x00);
+            dev->interface->write_register(REG_0xA6, 0xf6);
             // blinking led
-            dev->write_register(0x7e, 0x04);
+            dev->interface->write_register(0x7e, 0x04);
             break;
         case GpioId::G4050:
-            dev->write_register(REG_0xA7, 0xfe);
-            dev->write_register(REG_0xA8, 0x3e);
-            dev->write_register(REG_0xA9, 0x06);
+            dev->interface->write_register(REG_0xA7, 0xfe);
+            dev->interface->write_register(REG_0xA8, 0x3e);
+            dev->interface->write_register(REG_0xA9, 0x06);
             if ((reg->get8(0x05) & REG_0x05_DPIHW) == REG_0x05_DPIHW_600) {
-                dev->write_register(REG_0x6C, 0x20);
-                dev->write_register(REG_0xA6, 0x44);
+                dev->interface->write_register(REG_0x6C, 0x20);
+                dev->interface->write_register(REG_0xA6, 0x44);
             } else {
-                dev->write_register(REG_0x6C, 0x60);
-                dev->write_register(REG_0xA6, 0x46);
+                dev->interface->write_register(REG_0x6C, 0x60);
+                dev->interface->write_register(REG_0xA6, 0x46);
             }
 
             if (reg->state.is_xpa_on && reg->state.is_lamp_on) {
@@ -1708,7 +1708,7 @@ void CommandSetGl843::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
             }
 
             // blinking led
-            dev->write_register(REG_0x7E, 0x01);
+            dev->interface->write_register(REG_0x7E, 0x01);
             break;
         case GpioId::CANON_8400F:
         case GpioId::CANON_8600F:
@@ -1734,17 +1734,17 @@ void CommandSetGl843::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
     }
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
     // enable scan and motor
-    uint8_t val = dev->read_register(REG_0x01);
+    uint8_t val = dev->interface->read_register(REG_0x01);
     val |= REG_0x01_SCAN;
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
 
     if (start_motor) {
-        dev->write_register(REG_0x0F, 1);
+        dev->interface->write_register(REG_0x0F, 1);
     } else {
-        dev->write_register(REG_0x0F, 0);
+        dev->interface->write_register(REG_0x0F, 0);
     }
 }
 
@@ -1756,7 +1756,7 @@ void CommandSetGl843::end_scan(Genesys_Device* dev, Genesys_Register_Set* reg,
     DBG_HELPER_ARGS(dbg, "check_stop = %d", check_stop);
 
     // post scan gpio
-    dev->write_register(0x7e, 0x00);
+    dev->interface->write_register(0x7e, 0x00);
 
     // turn off XPA lamp if needed
     // BUG: the if condition below probably shouldn't be enabled when XPA is off
@@ -1787,7 +1787,7 @@ static void gl843_park_xpa_lamp(Genesys_Device* dev)
     local_reg.set24(REG_FEEDL, 0xbdcd);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
   /* set up for reverse and no scan */
     r = sanei_genesys_get_address (&local_reg, REG_0x02);
@@ -1796,7 +1796,7 @@ static void gl843_park_xpa_lamp(Genesys_Device* dev)
     r->value &= ~REG_0x01_SCAN;
 
     // write to scanner and start action
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
     gl843_set_xpa_motor_power(dev, true);
     try {
         gl843_start_action(dev);
@@ -1805,7 +1805,7 @@ static void gl843_park_xpa_lamp(Genesys_Device* dev)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1897,7 +1897,7 @@ void CommandSetGl843::slow_back_home(Genesys_Device* dev, bool wait_until_home)
     gl843_init_scan_regs(dev, sensor, &local_reg, session);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
   /* set up for reverse and no scan */
     r = sanei_genesys_get_address(&local_reg, REG_0x02);
@@ -1905,7 +1905,7 @@ void CommandSetGl843::slow_back_home(Genesys_Device* dev, bool wait_until_home)
     r = sanei_genesys_get_address(&local_reg, REG_0x01);
     r->value &= ~REG_0x01_SCAN;
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl843_start_action(dev);
@@ -1914,7 +1914,7 @@ void CommandSetGl843::slow_back_home(Genesys_Device* dev, bool wait_until_home)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1990,7 +1990,7 @@ void CommandSetGl843::search_start_position(Genesys_Device* dev) const
     gl843_init_scan_regs(dev, sensor, &local_reg, session);
 
     // send to scanner
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     dev->cmd_set->begin_scan(dev, sensor, &local_reg, true);
 
@@ -2058,7 +2058,7 @@ void CommandSetGl843::init_regs_for_coarse_calibration(Genesys_Device* dev,
   DBG(DBG_info, "%s: optical sensor res: %d dpi, actual res: %d\n", __func__,
       sensor.optical_res / sensor.ccd_pixels_per_system_pixel(), dev->settings.xres);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 /** @brief moves the slider to steps at motor base dpi
@@ -2101,15 +2101,15 @@ static void gl843_feed(Genesys_Device* dev, unsigned int steps)
     gl843_init_scan_regs(dev, sensor, &local_reg, session);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
-    dev->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
 
   /* set up for no scan */
   r = sanei_genesys_get_address(&local_reg, REG_0x01);
     r->value &= ~REG_0x01_SCAN;
 
     // send registers
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl843_start_action(dev);
@@ -2118,7 +2118,7 @@ static void gl843_feed(Genesys_Device* dev, unsigned int steps)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -2226,7 +2226,7 @@ void CommandSetGl843::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
 
   dev->scanhead_position_in_steps += dev->calib_lines + move;
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 /** @brief set up registers for the actual scan
@@ -2387,7 +2387,7 @@ SensorExposure CommandSetGl843::led_calibration(Genesys_Device* dev, const Genes
 
     gl843_init_scan_regs(dev, calib_sensor, &regs, session);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
 /*
    we try to get equal bright leds here:
@@ -2413,7 +2413,7 @@ SensorExposure CommandSetGl843::led_calibration(Genesys_Device* dev, const Genes
 
       sanei_genesys_set_exposure(regs, calib_sensor.exposure);
 
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
 
       DBG(DBG_info, "%s: starting first line reading\n", __func__);
         dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
@@ -2618,7 +2618,7 @@ void CommandSetGl843::offset_calibration(Genesys_Device* dev, const Genesys_Sens
     dev->cmd_set->set_fe(dev, calib_sensor, AFE_SET);
 
     // scan with bottom AFE settings
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
     DBG(DBG_info, "%s: starting first line reading\n", __func__);
 
     dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
@@ -2647,7 +2647,7 @@ void CommandSetGl843::offset_calibration(Genesys_Device* dev, const Genesys_Sens
     dev->cmd_set->set_fe(dev, calib_sensor, AFE_SET);
 
     // scan with top AFE values
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
     DBG(DBG_info, "%s: starting second line reading\n", __func__);
 
     dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
@@ -2682,7 +2682,7 @@ void CommandSetGl843::offset_calibration(Genesys_Device* dev, const Genesys_Sens
         dev->cmd_set->set_fe(dev, calib_sensor, AFE_SET);
 
         // scan with no move
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
       DBG(DBG_info, "%s: starting second line reading\n", __func__);
         dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
         second_line = read_unshuffled_image_from_scanner(dev, session,
@@ -2824,7 +2824,7 @@ void CommandSetGl843::coarse_gain_calibration(Genesys_Device* dev, const Genesys
 
     sanei_genesys_set_motor_power(regs, false);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     dev->cmd_set->set_fe(dev, calib_sensor, AFE_SET);
     dev->cmd_set->begin_scan(dev, calib_sensor, &regs, true);
@@ -2928,7 +2928,7 @@ void CommandSetGl843::init_regs_for_warmup(Genesys_Device* dev, const Genesys_Se
     gl843_init_scan_regs(dev, calib_sensor, reg, session);
 
   sanei_genesys_set_motor_power(*reg, false);
-    dev->write_registers(*reg);
+    dev->interface->write_registers(*reg);
 }
 
 /**
@@ -2943,7 +2943,7 @@ static void gl843_init_gpio(Genesys_Device* dev)
     DBG_HELPER(dbg);
     apply_registers_ordered(dev->gpo.regs, { 0x6e, 0x6f }, [&](const GenesysRegisterSetting& reg)
     {
-        dev->write_register(reg.address, reg.value);
+        dev->interface->write_register(reg.address, reg.value);
     });
 }
 
@@ -2957,8 +2957,8 @@ void CommandSetGl843::asic_boot(Genesys_Device* dev, bool cold) const
   uint8_t val;
 
     if (cold) {
-        dev->write_register(0x0e, 0x01);
-        dev->write_register(0x0e, 0x00);
+        dev->interface->write_register(0x0e, 0x01);
+        dev->interface->write_register(0x0e, 0x00);
     }
 
   if(dev->usb_mode == 1)
@@ -2972,9 +2972,9 @@ void CommandSetGl843::asic_boot(Genesys_Device* dev, bool cold) const
     dev->interface->write_0x8c(0x0f, val);
 
     // test CHKVER
-    val = dev->read_register(REG_0x40);
+    val = dev->interface->read_register(REG_0x40);
     if (val & REG_0x40_CHKVER) {
-        val = dev->read_register(0x00);
+        val = dev->interface->read_register(0x00);
         DBG(DBG_info, "%s: reported version for genesys chip is 0x%02x\n", __func__, val);
     }
 
@@ -2983,18 +2983,18 @@ void CommandSetGl843::asic_boot(Genesys_Device* dev, bool cold) const
 
     if (dev->model->model_id == ModelId::CANON_8600F) {
         // turns on vref control for maximum current of the motor driver
-        dev->write_register(REG_0x6B, 0x72);
+        dev->interface->write_register(REG_0x6B, 0x72);
     } else {
-        dev->write_register(REG_0x6B, 0x02);
+        dev->interface->write_register(REG_0x6B, 0x02);
     }
 
     // Write initial registers
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
   // Enable DRAM by setting a rising edge on bit 3 of reg 0x0b
     val = dev->reg.find_reg(0x0b).value & REG_0x0B_DRAMSEL;
     val = (val | REG_0x0B_ENBDRAM);
-    dev->write_register(REG_0x0B, val);
+    dev->interface->write_register(REG_0x0B, val);
   dev->reg.find_reg(0x0b).value = val;
 
     if (dev->model->model_id == ModelId::CANON_8400F) {
@@ -3031,7 +3031,7 @@ void CommandSetGl843::asic_boot(Genesys_Device* dev, bool cold) const
 
     val = (dev->reg.find_reg(0x0b).value & ~REG_0x0B_CLKSET) | clock_freq;
 
-    dev->write_register(REG_0x0B, val);
+    dev->interface->write_register(REG_0x0B, val);
   dev->reg.find_reg(0x0b).value = val;
 
   /* prevent further writings by bulk write register */
@@ -3040,14 +3040,14 @@ void CommandSetGl843::asic_boot(Genesys_Device* dev, bool cold) const
     if (dev->model->model_id != ModelId::CANON_8600F) {
       // set up end access
       // FIXME: this is overwritten in gl843_init_gpio
-        dev->write_register(REG_0xA7, 0x04);
-        dev->write_register(REG_0xA9, 0x00);
+        dev->interface->write_register(REG_0xA7, 0x04);
+        dev->interface->write_register(REG_0xA9, 0x00);
     }
 
     // set RAM read address
-    dev->write_register(REG_0x29, 0x00);
-    dev->write_register(REG_0x2A, 0x00);
-    dev->write_register(REG_0x2B, 0x00);
+    dev->interface->write_register(REG_0x29, 0x00);
+    dev->interface->write_register(REG_0x2A, 0x00);
+    dev->interface->write_register(REG_0x2B, 0x00);
 
     // setup gpio
     gl843_init_gpio(dev);
@@ -3075,7 +3075,7 @@ void CommandSetGl843::update_hardware_sensors(Genesys_Scanner* s) const
      any of them.
    */
 
-    uint8_t val = s->dev->read_register(REG_0x6D);
+    uint8_t val = s->dev->interface->read_register(REG_0x6D);
 
   switch (s->dev->model->gpio_id)
     {
@@ -3179,7 +3179,7 @@ void CommandSetGl843::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
         r->value |= REG_0x02_MTRREV;
     }
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     dev->cmd_set->begin_scan(dev, calib_sensor, &local_reg, true);
 
@@ -3204,7 +3204,7 @@ void CommandSetGl843::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
   found = 0;
   while (pass < 20 && !found)
     {
-        dev->write_registers(local_reg);
+        dev->interface->write_registers(local_reg);
 
         // now start scan
         dev->cmd_set->begin_scan(dev, calib_sensor, &local_reg, true);
diff --git a/backend/genesys/gl846.cpp b/backend/genesys/gl846.cpp
index e44695f40..afcd600f9 100644
--- a/backend/genesys/gl846.cpp
+++ b/backend/genesys/gl846.cpp
@@ -338,9 +338,9 @@ static void gl846_homsnr_gpio(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
 
-    uint8_t val = dev->read_register(REG_0x6C);
+    uint8_t val = dev->interface->read_register(REG_0x6C);
     val |= 0x41;
-    dev->write_register(REG_0x6C, val);
+    dev->interface->write_register(REG_0x6C, val);
 }
 
 // Set values of analog frontend
@@ -504,7 +504,7 @@ static void gl846_init_motor_regs_scan(Genesys_Device* dev,
 
   /* hi res motor speed GPIO */
   /*
-    uint8_t effective = dev->read_register(REG_0x6C);
+    uint8_t effective = dev->interface->read_register(REG_0x6C);
   */
 
   /* if quarter step, bipolar Vref2 */
@@ -524,14 +524,14 @@ static void gl846_init_motor_regs_scan(Genesys_Device* dev,
     {
       val = effective;
     }
-    dev->write_register(REG_0x6C, val);
+    dev->interface->write_register(REG_0x6C, val);
     */
 
   /* effective scan */
   /*
-    effective = dev->read_register(REG_0x6C);
+    effective = dev->interface->read_register(REG_0x6C);
     val = effective | REG_0x6C_GPIO10;
-    dev->write_register(REG_0x6C, val);
+    dev->interface->write_register(REG_0x6C, val);
   */
 
     if(dev->model->gpio_id == GpioId::IMG101) {
@@ -542,7 +542,7 @@ static void gl846_init_motor_regs_scan(Genesys_Device* dev,
         {
           val=0;
         }
-        dev->write_register(REG_0x7E, val);
+        dev->interface->write_register(REG_0x7E, val);
     }
 
   min_restep=scan_steps/2-1;
@@ -868,7 +868,7 @@ void CommandSetGl846::set_powersaving(Genesys_Device* dev, int delay /* in minut
 static void gl846_start_action(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x01);
+    dev->interface->write_register(0x0f, 0x01);
 }
 
 static void gl846_stop_action(Genesys_Device* dev)
@@ -885,7 +885,7 @@ static void gl846_stop_action(Genesys_Device* dev)
       sanei_genesys_print_status (val);
     }
 
-    uint8_t val40 = dev->read_register(REG_0x40);
+    uint8_t val40 = dev->interface->read_register(REG_0x40);
 
   /* only stop action if needed */
     if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG)) {
@@ -897,7 +897,7 @@ static void gl846_stop_action(Genesys_Device* dev)
     val = dev->reg.get8(REG_0x01);
     val &= ~REG_0x01_SCAN;
     dev->reg.set8(REG_0x01, val);
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
   sanei_genesys_sleep_ms(100);
 
   loop = 10;
@@ -908,7 +908,7 @@ static void gl846_stop_action(Genesys_Device* dev)
         {
           sanei_genesys_print_status (val);
         }
-        val40 = dev->read_register(REG_0x40);
+        val40 = dev->interface->read_register(REG_0x40);
 
       /* if scanner is in command mode, we are done */
         if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG) &&
@@ -935,25 +935,25 @@ void CommandSetGl846::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
 
   /* XXX STEF XXX SCAN GPIO */
   /*
-    val = dev->read_register(REG_0x6C);
-    dev->write_register(REG_0x6C, val);
+    val = dev->interface->read_register(REG_0x6C);
+    dev->interface->write_register(REG_0x6C, val);
   */
 
     val = REG_0x0D_CLRLNCNT;
-    dev->write_register(REG_0x0D, val);
+    dev->interface->write_register(REG_0x0D, val);
     val = REG_0x0D_CLRMCNT;
-    dev->write_register(REG_0x0D, val);
+    dev->interface->write_register(REG_0x0D, val);
 
-    val = dev->read_register(REG_0x01);
+    val = dev->interface->read_register(REG_0x01);
     val |= REG_0x01_SCAN;
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
     r = sanei_genesys_get_address (reg, REG_0x01);
   r->value = val;
 
     if (start_motor) {
-        dev->write_register(REG_0x0F, 1);
+        dev->interface->write_register(REG_0x0F, 1);
     } else {
-        dev->write_register(REG_0x0F, 0);
+        dev->interface->write_register(REG_0x0F, 0);
     }
 }
 
@@ -1040,13 +1040,13 @@ void CommandSetGl846::slow_back_home(Genesys_Device* dev, bool wait_until_home)
   dev->settings.scan_mode=scan_mode;
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
   /* set up for reverse */
     r = sanei_genesys_get_address(&local_reg, REG_0x02);
     r->value |= REG_0x02_MTRREV;
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl846_start_action(dev);
@@ -1057,7 +1057,7 @@ void CommandSetGl846::slow_back_home(Genesys_Device* dev, bool wait_until_home)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1131,7 +1131,7 @@ void CommandSetGl846::search_start_position(Genesys_Device* dev) const
     gl846_init_scan_regs(dev, sensor, &local_reg, session);
 
     // send to scanner
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
   size = pixels * dev->model->search_lines;
 
@@ -1195,7 +1195,7 @@ void CommandSetGl846::init_regs_for_coarse_calibration(Genesys_Device* dev,
     DBG(DBG_info, "%s: optical sensor res: %d dpi, actual res: %d\n", __func__,
         sensor.optical_res / sensor.ccd_pixels_per_system_pixel(), dev->settings.xres);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 /** @brief moves the slider to steps at motor base dpi
@@ -1240,15 +1240,15 @@ static void gl846_feed(Genesys_Device* dev, unsigned int steps)
     local_reg.set24(REG_EXPB, 0);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
-    dev->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
 
   /* set up for no scan */
     r = sanei_genesys_get_address(&local_reg, REG_0x01);
     r->value &= ~REG_0x01_SCAN;
 
     // send registers
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl846_start_action(dev);
@@ -1259,7 +1259,7 @@ static void gl846_feed(Genesys_Device* dev, unsigned int steps)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1323,7 +1323,7 @@ void CommandSetGl846::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
 
     gl846_init_scan_regs(dev, sensor, &regs, session);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
   /* we use GENESYS_FLAG_SHADING_REPARK */
   dev->scanhead_position_in_steps = 0;
@@ -1474,7 +1474,7 @@ void CommandSetGl846::send_shading_data(Genesys_Device* dev, const Genesys_Senso
           ptr+=4;
         }
 
-        val = dev->read_register(0xd0+i);
+        val = dev->interface->read_register(0xd0+i);
         addr = val * 8192 + 0x10000000;
         dev->interface->write_ahb(addr, pixels, buffer.data());
     }
@@ -1565,7 +1565,7 @@ SensorExposure CommandSetGl846::led_calibration(Genesys_Device* dev, const Genes
         regs.set16(REG_EXPB, exp[2]);
 
         // write registers and scan data
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
 
       DBG(DBG_info, "%s: starting line reading\n", __func__);
         begin_scan(dev, sensor, &regs, true);
@@ -1658,17 +1658,17 @@ static void gl846_init_gpio(Genesys_Device* dev)
                             static_cast<unsigned>(dev->model->sensor_id));
     }
 
-    dev->write_register(REG_0xA7, gpios[idx].ra7);
-    dev->write_register(REG_0xA6, gpios[idx].ra6);
+    dev->interface->write_register(REG_0xA7, gpios[idx].ra7);
+    dev->interface->write_register(REG_0xA6, gpios[idx].ra6);
 
-    dev->write_register(REG_0x6B, gpios[idx].r6b);
-    dev->write_register(REG_0x6C, gpios[idx].r6c);
-    dev->write_register(REG_0x6D, gpios[idx].r6d);
-    dev->write_register(REG_0x6E, gpios[idx].r6e);
-    dev->write_register(REG_0x6F, gpios[idx].r6f);
+    dev->interface->write_register(REG_0x6B, gpios[idx].r6b);
+    dev->interface->write_register(REG_0x6C, gpios[idx].r6c);
+    dev->interface->write_register(REG_0x6D, gpios[idx].r6d);
+    dev->interface->write_register(REG_0x6E, gpios[idx].r6e);
+    dev->interface->write_register(REG_0x6F, gpios[idx].r6f);
 
-    dev->write_register(REG_0xA8, gpios[idx].ra8);
-    dev->write_register(REG_0xA9, gpios[idx].ra9);
+    dev->interface->write_register(REG_0xA8, gpios[idx].ra8);
+    dev->interface->write_register(REG_0xA9, gpios[idx].ra9);
 }
 
 /**
@@ -1692,7 +1692,7 @@ static void gl846_init_memory_layout(Genesys_Device* dev)
 
   /* CLKSET and DRAMSEL */
   val = layouts[idx].dramsel;
-    dev->write_register(REG_0x0B, val);
+    dev->interface->write_register(REG_0x0B, val);
   dev->reg.find_reg(0x0b).value = val;
 
   /* prevent further writings by bulk write register */
@@ -1701,7 +1701,7 @@ static void gl846_init_memory_layout(Genesys_Device* dev)
   /* setup base address for shading and scanned data. */
   for(i=0;i<10;i++)
     {
-      dev->write_register(0xe0+i, layouts[idx].rx[i]);
+      dev->interface->write_register(0xe0+i, layouts[idx].rx[i]);
     }
 }
 
@@ -1715,8 +1715,8 @@ void CommandSetGl846::asic_boot(Genesys_Device* dev, bool cold) const
 
     // reset ASIC if cold boot
     if (cold) {
-        dev->write_register(0x0e, 0x01);
-        dev->write_register(0x0e, 0x00);
+        dev->interface->write_register(0x0e, 0x01);
+        dev->interface->write_register(0x0e, 0x00);
     }
 
   if(dev->usb_mode == 1)
@@ -1730,9 +1730,9 @@ void CommandSetGl846::asic_boot(Genesys_Device* dev, bool cold) const
     dev->interface->write_0x8c(0x0f, val);
 
     // test CHKVER
-    val = dev->read_register(REG_0x40);
+    val = dev->interface->read_register(REG_0x40);
     if (val & REG_0x40_CHKVER) {
-        val = dev->read_register(0x00);
+        val = dev->interface->read_register(0x00);
         DBG(DBG_info, "%s: reported version for genesys chip is 0x%02x\n", __func__, val);
     }
 
@@ -1740,19 +1740,19 @@ void CommandSetGl846::asic_boot(Genesys_Device* dev, bool cold) const
   gl846_init_registers (dev);
 
     // Write initial registers
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
   /* Enable DRAM by setting a rising edge on bit 3 of reg 0x0b */
     val = dev->reg.find_reg(0x0b).value & REG_0x0B_DRAMSEL;
     val = (val | REG_0x0B_ENBDRAM);
-    dev->write_register(REG_0x0B, val);
+    dev->interface->write_register(REG_0x0B, val);
   dev->reg.find_reg(0x0b).value = val;
 
   /* CIS_LINE */
   if (dev->model->is_cis)
     {
         SETREG(0x08, REG_0x08_CIS_LINE);
-        dev->write_register(0x08, dev->reg.find_reg(0x08).value);
+        dev->interface->write_register(0x08, dev->reg.find_reg(0x08).value);
     }
 
     // set up clocks
@@ -1766,7 +1766,7 @@ void CommandSetGl846::asic_boot(Genesys_Device* dev, bool cold) const
     gl846_init_memory_layout(dev);
 
   SETREG (0xf8, 0x05);
-    dev->write_register(0xf8, dev->reg.find_reg(0xf8).value);
+    dev->interface->write_register(0xf8, dev->reg.find_reg(0xf8).value);
 }
 
 /**
@@ -1797,7 +1797,7 @@ void CommandSetGl846::update_hardware_sensors(Genesys_Scanner* s) const
         email=0x04;
         copy=0x08;
     }
-    val = s->dev->read_register(REG_0x6D);
+    val = s->dev->interface->read_register(REG_0x6D);
 
     s->buttons[BUTTON_SCAN_SW].write((val & scan) == 0);
     s->buttons[BUTTON_FILE_SW].write((val & file) == 0);
@@ -1870,7 +1870,7 @@ void CommandSetGl846::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
         r->value |= REG_0x02_MTRREV;
     }
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     begin_scan(dev, sensor, &local_reg, true);
 
@@ -1894,7 +1894,7 @@ void CommandSetGl846::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
   found = 0;
   while (pass < 20 && !found)
     {
-        dev->write_registers(local_reg);
+        dev->interface->write_registers(local_reg);
 
         // now start scan
         begin_scan(dev, sensor, &local_reg, true);
@@ -2049,7 +2049,7 @@ void CommandSetGl846::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   int top, bottom, black_pixels, pixels;
 
     // no gain nor offset for AKM AFE
-    uint8_t reg04 = dev->read_register(REG_0x04);
+    uint8_t reg04 = dev->interface->read_register(REG_0x04);
     if ((reg04 & REG_0x04_FESET) == 0x02) {
       return;
     }
@@ -2101,7 +2101,7 @@ void CommandSetGl846::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   dev->frontend.set_offset(2, bottom);
 
     set_fe(dev, sensor, AFE_SET);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
   DBG(DBG_info, "%s: starting first line reading\n", __func__);
     begin_scan(dev, sensor, &regs, true);
     sanei_genesys_read_data_from_scanner(dev, first_line.data(), total_size);
@@ -2122,7 +2122,7 @@ void CommandSetGl846::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   dev->frontend.set_offset(1, top);
   dev->frontend.set_offset(2, top);
     set_fe(dev, sensor, AFE_SET);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
   DBG(DBG_info, "%s: starting second line reading\n", __func__);
     begin_scan(dev, sensor, &regs, true);
     sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
@@ -2142,7 +2142,7 @@ void CommandSetGl846::offset_calibration(Genesys_Device* dev, const Genesys_Sens
 
         // scan with no move
         set_fe(dev, sensor, AFE_SET);
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
       DBG(DBG_info, "%s: starting second line reading\n", __func__);
         begin_scan(dev, sensor, &regs, true);
         sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
@@ -2190,7 +2190,7 @@ void CommandSetGl846::coarse_gain_calibration(Genesys_Device* dev, const Genesys
   DBG(DBG_proc, "%s: dpi = %d\n", __func__, dpi);
 
     // no gain nor offset for AKM AFE
-    uint8_t reg04 = dev->read_register(REG_0x04);
+    uint8_t reg04 = dev->interface->read_register(REG_0x04);
     if ((reg04 & REG_0x04_FESET) == 0x02) {
       return;
     }
@@ -2237,7 +2237,7 @@ void CommandSetGl846::coarse_gain_calibration(Genesys_Device* dev, const Genesys
 
     sanei_genesys_set_motor_power(regs, false);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     total_size = pixels * channels * (16 / session.params.depth) * lines;
 
diff --git a/backend/genesys/gl847.cpp b/backend/genesys/gl847.cpp
index 7dcca16a6..fdba942c8 100644
--- a/backend/genesys/gl847.cpp
+++ b/backend/genesys/gl847.cpp
@@ -264,10 +264,10 @@ gl847_init_registers (Genesys_Device * dev)
 
       /* we write to these registers only once */
       val=0;
-        dev->write_register(REG_0x7E, val);
-        dev->write_register(REG_0x9E, val);
-        dev->write_register(REG_0x9F, val);
-        dev->write_register(REG_0xAB, val);
+        dev->interface->write_register(REG_0x7E, val);
+        dev->interface->write_register(REG_0x9E, val);
+        dev->interface->write_register(REG_0x9F, val);
+        dev->interface->write_register(REG_0xAB, val);
     }
 
     const auto& sensor = sanei_genesys_find_sensor_any(dev);
@@ -365,13 +365,13 @@ static void gl847_homsnr_gpio(Genesys_Device* dev)
     uint8_t val;
 
     if (dev->model->gpio_id == GpioId::CANON_LIDE_700F) {
-        val = dev->read_register(REG_0x6C);
+        val = dev->interface->read_register(REG_0x6C);
         val &= ~REG_0x6C_GPIO10;
-        dev->write_register(REG_0x6C, val);
+        dev->interface->write_register(REG_0x6C, val);
     } else {
-        val = dev->read_register(REG_0x6C);
+        val = dev->interface->read_register(REG_0x6C);
         val |= REG_0x6C_GPIO10;
-        dev->write_register(REG_0x6C, val);
+        dev->interface->write_register(REG_0x6C, val);
     }
 }
 
@@ -384,7 +384,7 @@ void CommandSetGl847::set_fe(Genesys_Device* dev, const Genesys_Sensor& sensor,
 
     (void) sensor;
 
-    uint8_t val = dev->read_register(REG_0x04);
+    uint8_t val = dev->interface->read_register(REG_0x04);
     uint8_t frontend_type = val & REG_0x04_FESET;
 
     // route to AD devices
@@ -536,7 +536,7 @@ static void gl847_init_motor_regs_scan(Genesys_Device* dev,
     tgtime = 1<<(r->value & REG_0x1C_TGTIME);
 
     // hi res motor speed GPIO
-    uint8_t effective = dev->read_register(REG_0x6C);
+    uint8_t effective = dev->interface->read_register(REG_0x6C);
 
     // if quarter step, bipolar Vref2
 
@@ -547,12 +547,12 @@ static void gl847_init_motor_regs_scan(Genesys_Device* dev,
     } else {
         val = effective;
     }
-    dev->write_register(REG_0x6C, val);
+    dev->interface->write_register(REG_0x6C, val);
 
     // effective scan
-    effective = dev->read_register(REG_0x6C);
+    effective = dev->interface->read_register(REG_0x6C);
     val = effective | REG_0x6C_GPIO10;
-    dev->write_register(REG_0x6C, val);
+    dev->interface->write_register(REG_0x6C, val);
 
   min_restep=scan_steps/2-1;
     if (min_restep < 1) {
@@ -873,7 +873,7 @@ void CommandSetGl847::set_powersaving(Genesys_Device* dev, int delay /* in minut
 static void gl847_start_action(Genesys_Device* dev)
 {
     DBG_HELPER(dbg);
-    dev->write_register(0x0f, 0x01);
+    dev->interface->write_register(0x0f, 0x01);
 }
 
 static void gl847_stop_action(Genesys_Device* dev)
@@ -890,7 +890,7 @@ static void gl847_stop_action(Genesys_Device* dev)
       sanei_genesys_print_status (val);
     }
 
-    uint8_t val40 = dev->read_register(REG_0x40);
+    uint8_t val40 = dev->interface->read_register(REG_0x40);
 
   /* only stop action if needed */
     if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG)) {
@@ -902,7 +902,7 @@ static void gl847_stop_action(Genesys_Device* dev)
     val = dev->reg.get8(REG_0x01);
     val &= ~REG_0x01_SCAN;
     dev->reg.set8(REG_0x01, val);
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
 
   sanei_genesys_sleep_ms(100);
 
@@ -914,7 +914,7 @@ static void gl847_stop_action(Genesys_Device* dev)
 	{
 	  sanei_genesys_print_status (val);
 	}
-        val40 = dev->read_register(REG_0x40);
+        val40 = dev->interface->read_register(REG_0x40);
 
       /* if scanner is in command mode, we are done */
         if (!(val40 & REG_0x40_DATAENB) && !(val40 & REG_0x40_MOTMFLG) &&
@@ -941,26 +941,26 @@ void CommandSetGl847::begin_scan(Genesys_Device* dev, const Genesys_Sensor& sens
 
     // clear GPIO 10
     if (dev->model->gpio_id != GpioId::CANON_LIDE_700F) {
-        val = dev->read_register(REG_0x6C);
+        val = dev->interface->read_register(REG_0x6C);
         val &= ~REG_0x6C_GPIO10;
-        dev->write_register(REG_0x6C, val);
+        dev->interface->write_register(REG_0x6C, val);
     }
 
     val = REG_0x0D_CLRLNCNT;
-    dev->write_register(REG_0x0D, val);
+    dev->interface->write_register(REG_0x0D, val);
     val = REG_0x0D_CLRMCNT;
-    dev->write_register(REG_0x0D, val);
+    dev->interface->write_register(REG_0x0D, val);
 
-    val = dev->read_register(REG_0x01);
+    val = dev->interface->read_register(REG_0x01);
     val |= REG_0x01_SCAN;
-    dev->write_register(REG_0x01, val);
+    dev->interface->write_register(REG_0x01, val);
     r = sanei_genesys_get_address (reg, REG_0x01);
   r->value = val;
 
     if (start_motor) {
-        dev->write_register(REG_0x0F, 1);
+        dev->interface->write_register(REG_0x0F, 1);
     } else {
-        dev->write_register(REG_0x0F, 0);
+        dev->interface->write_register(REG_0x0F, 0);
     }
 }
 
@@ -989,24 +989,24 @@ static void gl847_rewind(Genesys_Device* dev)
 
 
     // set motor reverse
-    uint8_t byte = dev->read_register(0x02);
+    uint8_t byte = dev->interface->read_register(0x02);
     byte |= 0x04;
-    dev->write_register(0x02, byte);
+    dev->interface->write_register(0x02, byte);
 
     // and start scan, then wait completion
     gl847_begin_scan(dev, dev->reg, true);
   do
     {
       sanei_genesys_sleep_ms(100);
-        byte = dev->read_register(REG_0x40);
+        byte = dev->interface->read_register(REG_0x40);
     } while (byte & REG_0x40_MOTMFLG);
 
     gl847_end_scan(dev, dev->reg, true);
 
     // restore direction
-    byte = dev->read_register(0x02);
+    byte = dev->interface->read_register(0x02);
     byte &= 0xfb;
-    dev->write_register(0x02, byte);
+    dev->interface->write_register(0x02, byte);
 }
 #endif
 
@@ -1085,13 +1085,13 @@ void CommandSetGl847::slow_back_home(Genesys_Device* dev, bool wait_until_home)
   dev->settings.scan_mode = scan_mode;
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT | REG_0x0D_CLRMCNT);
 
   /* set up for reverse */
     r = sanei_genesys_get_address (&local_reg, REG_0x02);
     r->value |= REG_0x02_MTRREV;
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl847_start_action(dev);
@@ -1100,7 +1100,7 @@ void CommandSetGl847::slow_back_home(Genesys_Device* dev, bool wait_until_home)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1174,7 +1174,7 @@ void CommandSetGl847::search_start_position(Genesys_Device* dev) const
     gl847_init_scan_regs(dev, sensor, &local_reg, session);
 
     // send to scanner
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
   size = pixels * dev->model->search_lines;
 
@@ -1238,7 +1238,7 @@ void CommandSetGl847::init_regs_for_coarse_calibration(Genesys_Device* dev,
   DBG(DBG_info, "%s: optical sensor res: %d dpi, actual res: %d\n", __func__,
       sensor.optical_res / sensor.ccd_pixels_per_system_pixel(), dev->settings.xres);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 }
 
 /** @brief moves the slider to steps at motor base dpi
@@ -1283,15 +1283,15 @@ static void gl847_feed(Genesys_Device* dev, unsigned int steps)
     local_reg.set24(REG_EXPB,0);
 
     // clear scan and feed count
-    dev->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
-    dev->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRLNCNT);
+    dev->interface->write_register(REG_0x0D, REG_0x0D_CLRMCNT);
 
   /* set up for no scan */
     r = sanei_genesys_get_address(&local_reg, REG_0x01);
     r->value &= ~REG_0x01_SCAN;
 
     // send registers
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     try {
         gl847_start_action(dev);
@@ -1300,7 +1300,7 @@ static void gl847_feed(Genesys_Device* dev, unsigned int steps)
         // restore original registers
         catch_all_exceptions(__func__, [&]()
         {
-            dev->write_registers(dev->reg);
+            dev->interface->write_registers(dev->reg);
         });
         throw;
     }
@@ -1356,7 +1356,7 @@ void CommandSetGl847::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
 
     gl847_init_scan_regs(dev, sensor, &regs, session);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
   /* we use GENESYS_FLAG_SHADING_REPARK */
   dev->scanhead_position_in_steps = 0;
@@ -1506,7 +1506,7 @@ void CommandSetGl847::send_shading_data(Genesys_Device* dev, const Genesys_Senso
           ptr+=4;
         }
 
-        val = dev->read_register(0xd0+i);
+        val = dev->interface->read_register(0xd0+i);
         addr = val * 8192 + 0x10000000;
         dev->interface->write_ahb(addr, pixels, buffer.data());
     }
@@ -1598,7 +1598,7 @@ SensorExposure CommandSetGl847::led_calibration(Genesys_Device* dev, const Genes
         regs.set16(REG_EXPB,exp[2]);
 
         // write registers and scan data
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
 
       DBG(DBG_info, "%s: starting line reading\n", __func__);
         begin_scan(dev, sensor, &regs, true);
@@ -1684,20 +1684,20 @@ static void gl847_init_gpio(Genesys_Device* dev)
                             static_cast<unsigned>(dev->model->sensor_id));
     }
 
-    dev->write_register(REG_0xA7, gpios[idx].ra7);
-    dev->write_register(REG_0xA6, gpios[idx].ra6);
+    dev->interface->write_register(REG_0xA7, gpios[idx].ra7);
+    dev->interface->write_register(REG_0xA6, gpios[idx].ra6);
 
-    dev->write_register(REG_0x6E, gpios[idx].r6e);
-    dev->write_register(REG_0x6C, 0x00);
+    dev->interface->write_register(REG_0x6E, gpios[idx].r6e);
+    dev->interface->write_register(REG_0x6C, 0x00);
 
-    dev->write_register(REG_0x6B, gpios[idx].r6b);
-    dev->write_register(REG_0x6C, gpios[idx].r6c);
-    dev->write_register(REG_0x6D, gpios[idx].r6d);
-    dev->write_register(REG_0x6E, gpios[idx].r6e);
-    dev->write_register(REG_0x6F, gpios[idx].r6f);
+    dev->interface->write_register(REG_0x6B, gpios[idx].r6b);
+    dev->interface->write_register(REG_0x6C, gpios[idx].r6c);
+    dev->interface->write_register(REG_0x6D, gpios[idx].r6d);
+    dev->interface->write_register(REG_0x6E, gpios[idx].r6e);
+    dev->interface->write_register(REG_0x6F, gpios[idx].r6f);
 
-    dev->write_register(REG_0xA8, gpios[idx].ra8);
-    dev->write_register(REG_0xA9, gpios[idx].ra9);
+    dev->interface->write_register(REG_0xA8, gpios[idx].ra8);
+    dev->interface->write_register(REG_0xA9, gpios[idx].ra9);
 }
 
 /**
@@ -1726,7 +1726,7 @@ static void gl847_init_memory_layout(Genesys_Device* dev)
 
   /* CLKSET nd DRAMSEL */
   val = layouts[idx].dramsel;
-    dev->write_register(REG_0x0B, val);
+    dev->interface->write_register(REG_0x0B, val);
   dev->reg.find_reg(0x0b).value = val;
 
   /* prevent further writings by bulk write register */
@@ -1735,48 +1735,48 @@ static void gl847_init_memory_layout(Genesys_Device* dev)
   /* setup base address for shading data. */
   /* values must be multiplied by 8192=0x4000 to give address on AHB */
   /* R-Channel shading bank0 address setting for CIS */
-    dev->write_register(0xd0, layouts[idx].rd0);
+    dev->interface->write_register(0xd0, layouts[idx].rd0);
   /* G-Channel shading bank0 address setting for CIS */
-    dev->write_register(0xd1, layouts[idx].rd1);
+    dev->interface->write_register(0xd1, layouts[idx].rd1);
   /* B-Channel shading bank0 address setting for CIS */
-    dev->write_register(0xd2, layouts[idx].rd2);
+    dev->interface->write_register(0xd2, layouts[idx].rd2);
 
   /* setup base address for scanned data. */
   /* values must be multiplied by 1024*2=0x0800 to give address on AHB */
   /* R-Channel ODD image buffer 0x0124->0x92000 */
   /* size for each buffer is 0x16d*1k word */
-    dev->write_register(0xe0, layouts[idx].re0);
-    dev->write_register(0xe1, layouts[idx].re1);
+    dev->interface->write_register(0xe0, layouts[idx].re0);
+    dev->interface->write_register(0xe1, layouts[idx].re1);
   /* R-Channel ODD image buffer end-address 0x0291->0x148800 => size=0xB6800*/
-    dev->write_register(0xe2, layouts[idx].re2);
-    dev->write_register(0xe3, layouts[idx].re3);
+    dev->interface->write_register(0xe2, layouts[idx].re2);
+    dev->interface->write_register(0xe3, layouts[idx].re3);
 
   /* R-Channel EVEN image buffer 0x0292 */
-    dev->write_register(0xe4, layouts[idx].re4);
-    dev->write_register(0xe5, layouts[idx].re5);
+    dev->interface->write_register(0xe4, layouts[idx].re4);
+    dev->interface->write_register(0xe5, layouts[idx].re5);
   /* R-Channel EVEN image buffer end-address 0x03ff*/
-    dev->write_register(0xe6, layouts[idx].re6);
-    dev->write_register(0xe7, layouts[idx].re7);
+    dev->interface->write_register(0xe6, layouts[idx].re6);
+    dev->interface->write_register(0xe7, layouts[idx].re7);
 
   /* same for green, since CIS, same addresses */
-    dev->write_register(0xe8, layouts[idx].re0);
-    dev->write_register(0xe9, layouts[idx].re1);
-    dev->write_register(0xea, layouts[idx].re2);
-    dev->write_register(0xeb, layouts[idx].re3);
-    dev->write_register(0xec, layouts[idx].re4);
-    dev->write_register(0xed, layouts[idx].re5);
-    dev->write_register(0xee, layouts[idx].re6);
-    dev->write_register(0xef, layouts[idx].re7);
+    dev->interface->write_register(0xe8, layouts[idx].re0);
+    dev->interface->write_register(0xe9, layouts[idx].re1);
+    dev->interface->write_register(0xea, layouts[idx].re2);
+    dev->interface->write_register(0xeb, layouts[idx].re3);
+    dev->interface->write_register(0xec, layouts[idx].re4);
+    dev->interface->write_register(0xed, layouts[idx].re5);
+    dev->interface->write_register(0xee, layouts[idx].re6);
+    dev->interface->write_register(0xef, layouts[idx].re7);
 
 /* same for blue, since CIS, same addresses */
-    dev->write_register(0xf0, layouts[idx].re0);
-    dev->write_register(0xf1, layouts[idx].re1);
-    dev->write_register(0xf2, layouts[idx].re2);
-    dev->write_register(0xf3, layouts[idx].re3);
-    dev->write_register(0xf4, layouts[idx].re4);
-    dev->write_register(0xf5, layouts[idx].re5);
-    dev->write_register(0xf6, layouts[idx].re6);
-    dev->write_register(0xf7, layouts[idx].re7);
+    dev->interface->write_register(0xf0, layouts[idx].re0);
+    dev->interface->write_register(0xf1, layouts[idx].re1);
+    dev->interface->write_register(0xf2, layouts[idx].re2);
+    dev->interface->write_register(0xf3, layouts[idx].re3);
+    dev->interface->write_register(0xf4, layouts[idx].re4);
+    dev->interface->write_register(0xf5, layouts[idx].re5);
+    dev->interface->write_register(0xf6, layouts[idx].re6);
+    dev->interface->write_register(0xf7, layouts[idx].re7);
 }
 
 /* *
@@ -1788,14 +1788,14 @@ void CommandSetGl847::asic_boot(Genesys_Device* dev, bool cold) const
 
     // reset ASIC if cold boot
     if (cold) {
-        dev->write_register(0x0e, 0x01);
-        dev->write_register(0x0e, 0x00);
+        dev->interface->write_register(0x0e, 0x01);
+        dev->interface->write_register(0x0e, 0x00);
     }
 
     // test CHKVER
-    uint8_t val = dev->read_register(REG_0x40);
+    uint8_t val = dev->interface->read_register(REG_0x40);
     if (val & REG_0x40_CHKVER) {
-        val = dev->read_register(0x00);
+        val = dev->interface->read_register(0x00);
         DBG(DBG_info, "%s: reported version for genesys chip is 0x%02x\n", __func__, val);
     }
 
@@ -1803,17 +1803,17 @@ void CommandSetGl847::asic_boot(Genesys_Device* dev, bool cold) const
   gl847_init_registers (dev);
 
     // Write initial registers
-    dev->write_registers(dev->reg);
+    dev->interface->write_registers(dev->reg);
 
   /* Enable DRAM by setting a rising edge on bit 3 of reg 0x0b */
     val = dev->reg.find_reg(0x0b).value & REG_0x0B_DRAMSEL;
     val = (val | REG_0x0B_ENBDRAM);
-    dev->write_register(REG_0x0B, val);
+    dev->interface->write_register(REG_0x0B, val);
     dev->reg.find_reg(0x0b).value = val;
 
   /* CIS_LINE */
     SETREG(0x08, REG_0x08_CIS_LINE);
-    dev->write_register(0x08, dev->reg.find_reg(0x08).value);
+    dev->interface->write_register(0x08, dev->reg.find_reg(0x08).value);
 
     // set up end access
     dev->interface->write_0x8c(0x10, 0x0b);
@@ -1826,7 +1826,7 @@ void CommandSetGl847::asic_boot(Genesys_Device* dev, bool cold) const
     gl847_init_memory_layout (dev);
 
   SETREG (0xf8, 0x01);
-    dev->write_register(0xf8, dev->reg.find_reg(0xf8).value);
+    dev->interface->write_register(0xf8, dev->reg.find_reg(0xf8).value);
 }
 
 /**
@@ -1862,7 +1862,7 @@ void CommandSetGl847::update_hardware_sensors(Genesys_Scanner* s) const
         email=0x04;
         copy=0x08;
     }
-    val = s->dev->read_register(REG_0x6D);
+    val = s->dev->interface->read_register(REG_0x6D);
 
     s->buttons[BUTTON_SCAN_SW].write((val & scan) == 0);
     s->buttons[BUTTON_FILE_SW].write((val & file) == 0);
@@ -1934,7 +1934,7 @@ void CommandSetGl847::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
         r->value |= REG_0x02_MTRREV;
     }
 
-    dev->write_registers(local_reg);
+    dev->interface->write_registers(local_reg);
 
     begin_scan(dev, sensor, &local_reg, true);
 
@@ -1958,7 +1958,7 @@ void CommandSetGl847::search_strip(Genesys_Device* dev, const Genesys_Sensor& se
   found = 0;
   while (pass < 20 && !found)
     {
-        dev->write_registers(local_reg);
+        dev->interface->write_registers(local_reg);
 
         // now start scan
         begin_scan(dev, sensor, &local_reg, true);
@@ -2114,7 +2114,7 @@ void CommandSetGl847::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   int top, bottom, black_pixels, pixels;
 
     // no gain nor offset for AKM AFE
-    uint8_t reg04 = dev->read_register(REG_0x04);
+    uint8_t reg04 = dev->interface->read_register(REG_0x04);
     if ((reg04 & REG_0x04_FESET) == 0x02) {
       return;
     }
@@ -2167,7 +2167,7 @@ void CommandSetGl847::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   dev->frontend.set_offset(2, bottom);
 
     set_fe(dev, sensor, AFE_SET);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
   DBG(DBG_info, "%s: starting first line reading\n", __func__);
     begin_scan(dev, sensor, &regs, true);
     sanei_genesys_read_data_from_scanner(dev, first_line.data(), total_size);
@@ -2188,7 +2188,7 @@ void CommandSetGl847::offset_calibration(Genesys_Device* dev, const Genesys_Sens
   dev->frontend.set_offset(1, top);
   dev->frontend.set_offset(2, top);
     set_fe(dev, sensor, AFE_SET);
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
   DBG(DBG_info, "%s: starting second line reading\n", __func__);
     begin_scan(dev, sensor, &regs, true);
     sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
@@ -2208,7 +2208,7 @@ void CommandSetGl847::offset_calibration(Genesys_Device* dev, const Genesys_Sens
 
         // scan with no move
         set_fe(dev, sensor, AFE_SET);
-        dev->write_registers(regs);
+        dev->interface->write_registers(regs);
       DBG(DBG_info, "%s: starting second line reading\n", __func__);
         begin_scan(dev, sensor, &regs, true);
         sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size);
@@ -2254,7 +2254,7 @@ void CommandSetGl847::coarse_gain_calibration(Genesys_Device* dev, const Genesys
   int val, code, lines;
 
     // no gain nor offset for AKM AFE
-    uint8_t reg04 = dev->read_register(REG_0x04);
+    uint8_t reg04 = dev->interface->read_register(REG_0x04);
     if ((reg04 & REG_0x04_FESET) == 0x02) {
       return;
     }
@@ -2301,7 +2301,7 @@ void CommandSetGl847::coarse_gain_calibration(Genesys_Device* dev, const Genesys
 
     sanei_genesys_set_motor_power(regs, false);
 
-    dev->write_registers(regs);
+    dev->interface->write_registers(regs);
 
     total_size = pixels * channels * (16 / session.params.depth) * lines;
 
diff --git a/backend/genesys/low.cpp b/backend/genesys/low.cpp
index 6a90edeba..c01231184 100644
--- a/backend/genesys/low.cpp
+++ b/backend/genesys/low.cpp
@@ -248,10 +248,10 @@ void sanei_genesys_set_buffer_address(Genesys_Device* dev, uint32_t addr)
 
   addr = addr >> 4;
 
-    dev->write_register(0x2b, (addr & 0xff));
+    dev->interface->write_register(0x2b, (addr & 0xff));
 
   addr = addr >> 8;
-    dev->write_register(0x2a, (addr & 0xff));
+    dev->interface->write_register(0x2a, (addr & 0xff));
 }
 
 /* ------------------------------------------------------------------------ */
@@ -267,7 +267,7 @@ std::uint8_t sanei_genesys_get_status(Genesys_Device* dev)
     if (dev->model->asic_type == AsicType::GL124) {
         address = 0x101;
     }
-    return dev->read_register(address);
+    return dev->interface->read_register(address);
 }
 
 /**
@@ -324,34 +324,34 @@ void sanei_genesys_read_valid_words(Genesys_Device* dev, unsigned int* words)
   switch (dev->model->asic_type)
     {
     case AsicType::GL124:
-            *words = dev->read_register(0x102) & 0x03;
-            *words = *words * 256 + dev->read_register(0x103);
-            *words = *words * 256 + dev->read_register(0x104);
-            *words = *words * 256 + dev->read_register(0x105);
+            *words = dev->interface->read_register(0x102) & 0x03;
+            *words = *words * 256 + dev->interface->read_register(0x103);
+            *words = *words * 256 + dev->interface->read_register(0x104);
+            *words = *words * 256 + dev->interface->read_register(0x105);
             break;
 
     case AsicType::GL845:
     case AsicType::GL846:
-            *words = dev->read_register(0x42) & 0x02;
-            *words = *words * 256 + dev->read_register(0x43);
-            *words = *words * 256 + dev->read_register(0x44);
-            *words = *words * 256 + dev->read_register(0x45);
+            *words = dev->interface->read_register(0x42) & 0x02;
+            *words = *words * 256 + dev->interface->read_register(0x43);
+            *words = *words * 256 + dev->interface->read_register(0x44);
+            *words = *words * 256 + dev->interface->read_register(0x45);
             break;
 
     case AsicType::GL847:
-            *words = dev->read_register(0x42) & 0x03;
-            *words = *words * 256 + dev->read_register(0x43);
-            *words = *words * 256 + dev->read_register(0x44);
-            *words = *words * 256 + dev->read_register(0x45);
+            *words = dev->interface->read_register(0x42) & 0x03;
+            *words = *words * 256 + dev->interface->read_register(0x43);
+            *words = *words * 256 + dev->interface->read_register(0x44);
+            *words = *words * 256 + dev->interface->read_register(0x45);
             break;
 
     default:
-            *words = dev->read_register(0x44);
-            *words += dev->read_register(0x43) * 256;
+            *words = dev->interface->read_register(0x44);
+            *words += dev->interface->read_register(0x43) * 256;
             if (dev->model->asic_type == AsicType::GL646) {
-                *words += ((dev->read_register(0x42) & 0x03) * 256 * 256);
+                *words += ((dev->interface->read_register(0x42) & 0x03) * 256 * 256);
             } else {
-                *words += ((dev->read_register(0x42) & 0x0f) * 256 * 256);
+                *words += ((dev->interface->read_register(0x42) & 0x0f) * 256 * 256);
             }
     }
 
@@ -366,18 +366,18 @@ void sanei_genesys_read_scancnt(Genesys_Device* dev, unsigned int* words)
     DBG_HELPER(dbg);
 
     if (dev->model->asic_type == AsicType::GL124) {
-        *words = (dev->read_register(0x10b) & 0x0f) << 16;
-        *words += (dev->read_register(0x10c) << 8);
-        *words += dev->read_register(0x10d);
+        *words = (dev->interface->read_register(0x10b) & 0x0f) << 16;
+        *words += (dev->interface->read_register(0x10c) << 8);
+        *words += dev->interface->read_register(0x10d);
     }
   else
     {
-        *words = dev->read_register(0x4d);
-        *words += dev->read_register(0x4c) * 256;
+        *words = dev->interface->read_register(0x4d);
+        *words += dev->interface->read_register(0x4c) * 256;
         if (dev->model->asic_type == AsicType::GL646) {
-            *words += ((dev->read_register(0x4b) & 0x03) * 256 * 256);
+            *words += ((dev->interface->read_register(0x4b) & 0x03) * 256 * 256);
         } else {
-            *words += ((dev->read_register(0x4b) & 0x0f) * 256 * 256);
+            *words += ((dev->interface->read_register(0x4b) & 0x0f) * 256 * 256);
         }
     }
 
@@ -518,20 +518,20 @@ void sanei_genesys_read_feed_steps(Genesys_Device* dev, unsigned int* steps)
     DBG_HELPER(dbg);
 
     if (dev->model->asic_type == AsicType::GL124) {
-        *steps = (dev->read_register(0x108) & 0x1f) << 16;
-        *steps += (dev->read_register(0x109) << 8);
-        *steps += dev->read_register(0x10a);
+        *steps = (dev->interface->read_register(0x108) & 0x1f) << 16;
+        *steps += (dev->interface->read_register(0x109) << 8);
+        *steps += dev->interface->read_register(0x10a);
     }
   else
     {
-        *steps = dev->read_register(0x4a);
-        *steps += dev->read_register(0x49) * 256;
+        *steps = dev->interface->read_register(0x4a);
+        *steps += dev->interface->read_register(0x49) * 256;
         if (dev->model->asic_type == AsicType::GL646) {
-            *steps += ((dev->read_register(0x48) & 0x03) * 256 * 256);
+            *steps += ((dev->interface->read_register(0x48) & 0x03) * 256 * 256);
         } else if (dev->model->asic_type == AsicType::GL841) {
-            *steps += ((dev->read_register(0x48) & 0x0f) * 256 * 256);
+            *steps += ((dev->interface->read_register(0x48) & 0x0f) * 256 * 256);
         } else {
-            *steps += ((dev->read_register(0x48) & 0x1f) * 256 * 256);
+            *steps += ((dev->interface->read_register(0x48) & 0x1f) * 256 * 256);
         }
     }
 
@@ -714,14 +714,14 @@ void sanei_genesys_send_gamma_table(Genesys_Device* dev, const Genesys_Sensor& s
     // loop sending gamma tables NOTE: 0x01000000 not 0x10000000
     for (i = 0; i < 3; i++) {
         // clear corresponding GMM_N bit
-        uint8_t val = dev->read_register(0xbd);
+        uint8_t val = dev->interface->read_register(0xbd);
         val &= ~(0x01 << i);
-        dev->write_register(0xbd, val);
+        dev->interface->write_register(0xbd, val);
 
         // clear corresponding GMM_F bit
-        val = dev->read_register(0xbe);
+        val = dev->interface->read_register(0xbe);
       val &= ~(0x01 << i);
-        dev->write_register(0xbe, val);
+        dev->interface->write_register(0xbe, val);
 
       // FIXME: currently the last word of each gamma table is not initialied, so to work around
       // unstable data, just set it to 0 which is the most likely value of uninitialized memory
@@ -730,8 +730,8 @@ void sanei_genesys_send_gamma_table(Genesys_Device* dev, const Genesys_Sensor& s
       gamma[size * 2 * i + size * 2 - 1] = 0;
 
       /* set GMM_Z */
-        dev->write_register(0xc5+2*i, gamma[size*2*i+1]);
-        dev->write_register(0xc6+2*i, gamma[size*2*i]);
+        dev->interface->write_register(0xc5+2*i, gamma[size*2*i+1]);
+        dev->interface->write_register(0xc6+2*i, gamma[size*2*i]);
 
         dev->interface->write_ahb(0x01000000 + 0x200 * i, (size-1) * 2,
                                   gamma.data() + i * size * 2+2);
@@ -1499,7 +1499,7 @@ void sanei_genesys_asic_init(Genesys_Device* dev, bool /*max_regs*/)
         check PWRBIT, if reset scanner has been freshly powered up. This bit will be set to later
         so that following reads can detect power down/up cycle
     */
-    if (dev->read_register(0x06) & 0x10) {
+    if (dev->interface->read_register(0x06) & 0x10) {
         cold = false;
     }
   DBG (DBG_info, "%s: device is %s\n", __func__, cold ? "cold" : "warm");
diff --git a/backend/genesys/scanner_interface_usb.cpp b/backend/genesys/scanner_interface_usb.cpp
index 079034d19..df0b73ee7 100644
--- a/backend/genesys/scanner_interface_usb.cpp
+++ b/backend/genesys/scanner_interface_usb.cpp
@@ -194,7 +194,7 @@ void ScannerInterfaceUsb::write_registers(const Genesys_Register_Set& regs)
         }
     } else {
         for (const auto& r : regs) {
-            dev_->write_register(r.address, r.value);
+            write_register(r.address, r.value);
         }
     }
 
@@ -389,11 +389,11 @@ std::uint16_t ScannerInterfaceUsb::read_fe_register(std::uint8_t address)
     reg.init_reg(0x50, address);
 
     // set up read address
-    dev_->write_registers(reg);
+    write_registers(reg);
 
     // read data
-    std::uint16_t value = dev_->read_register(0x46) << 8;
-    value |= dev_->read_register(0x47);
+    std::uint16_t value = read_register(0x46) << 8;
+    value |= read_register(0x47);
 
     DBG(DBG_io, "%s (0x%02x, 0x%04x)\n", __func__, address, value);
     return value;
@@ -413,7 +413,7 @@ void ScannerInterfaceUsb::write_fe_register(std::uint8_t address, std::uint16_t
         reg.init_reg(0x3b, value & 0xff);
     }
 
-    dev_->write_registers(reg);
+    write_registers(reg);
 }
 
 } // namespace genesys