diff --git a/backend/genesys/genesys.cpp b/backend/genesys/genesys.cpp
index 1bc44f06f..da033a7c5 100644
--- a/backend/genesys/genesys.cpp
+++ b/backend/genesys/genesys.cpp
@@ -4910,7 +4910,7 @@ static void probe_genesys_devices()
    of Genesys_Calibration_Cache as is.
 */
 static const char* CALIBRATION_IDENT = "sane_genesys";
-static const int CALIBRATION_VERSION = 27;
+static const int CALIBRATION_VERSION = 28;
 
 bool read_calibration(std::istream& str, Genesys_Device::Calibration& calibration,
                       const std::string& path)
diff --git a/backend/genesys/low.cpp b/backend/genesys/low.cpp
index cb943d6b6..19cbf2344 100644
--- a/backend/genesys/low.cpp
+++ b/backend/genesys/low.cpp
@@ -967,17 +967,8 @@ void compute_session(const Genesys_Device* dev, ScanSession& s, const Genesys_Se
         throw SaneException("Unsupported depth setting %d", s.params.depth);
     }
 
-    unsigned ccd_pixels_per_system_pixel = sensor.ccd_pixels_per_system_pixel();
-
     // compute optical and output resolutions
 
-    if (dev->model->asic_type == AsicType::GL843) {
-        // FIXME: this may be incorrect, but need more scanners to test
-        s.hwdpi_divisor = sensor.get_hwdpi_divisor_for_dpi(s.params.xres);
-    } else {
-        s.hwdpi_divisor = sensor.get_hwdpi_divisor_for_dpi(s.params.xres * ccd_pixels_per_system_pixel);
-    }
-
     s.ccd_size_divisor = sensor.get_ccd_size_divisor_for_dpi(s.params.xres);
     s.pixel_count_ratio = sensor.pixel_count_ratio;
 
diff --git a/backend/genesys/sensor.h b/backend/genesys/sensor.h
index 08b027883..bd73fc1dc 100644
--- a/backend/genesys/sensor.h
+++ b/backend/genesys/sensor.h
@@ -328,17 +328,12 @@ struct Genesys_Sensor {
 
     std::function<unsigned(const Genesys_Sensor&, unsigned)> get_register_hwdpi_fun;
     std::function<unsigned(const Genesys_Sensor&, unsigned)> get_ccd_size_divisor_fun;
-    std::function<unsigned(const Genesys_Sensor&, unsigned)> get_hwdpi_divisor_fun;
 
     unsigned get_register_hwdpi(unsigned xres) const { return get_register_hwdpi_fun(*this, xres); }
     unsigned get_ccd_size_divisor_for_dpi(unsigned xres) const
     {
         return get_ccd_size_divisor_fun(*this, xres);
     }
-    unsigned get_hwdpi_divisor_for_dpi(unsigned xres) const
-    {
-        return get_hwdpi_divisor_fun(*this, xres);
-    }
 
     // how many CCD pixels are processed per system pixel time. This corresponds to CKSEL + 1
     unsigned ccd_pixels_per_system_pixel() const
diff --git a/backend/genesys/settings.cpp b/backend/genesys/settings.cpp
index fe30bbe30..6a77de893 100644
--- a/backend/genesys/settings.cpp
+++ b/backend/genesys/settings.cpp
@@ -97,7 +97,6 @@ bool ScanSession::operator==(const ScanSession& other) const
 {
     return params == other.params &&
         computed == other.computed &&
-        hwdpi_divisor == other.hwdpi_divisor &&
         ccd_size_divisor == other.ccd_size_divisor &&
         optical_resolution == other.optical_resolution &&
         optical_pixels == other.optical_pixels &&
@@ -136,7 +135,6 @@ std::ostream& operator<<(std::ostream& out, const ScanSession& session)
 {
     out << "ScanSession{\n"
         << "    computed: " << session.computed << '\n'
-        << "    hwdpi_divisor: " << session.hwdpi_divisor << '\n'
         << "    ccd_size_divisor: " << session.ccd_size_divisor << '\n'
         << "    optical_resolution: " << session.optical_resolution << '\n'
         << "    optical_pixels: " << session.optical_pixels << '\n'
diff --git a/backend/genesys/settings.h b/backend/genesys/settings.h
index f174bd17b..111939ecb 100644
--- a/backend/genesys/settings.h
+++ b/backend/genesys/settings.h
@@ -211,10 +211,6 @@ struct ScanSession {
     // whether the session setup has been computed via compute_session()
     bool computed = false;
 
-    // specifies the reduction (if any) of hardware dpi on the Genesys chip side.
-    // except gl646
-    unsigned hwdpi_divisor = 1;
-
     // specifies the reduction (if any) of CCD effective dpi which is performed by latching the
     // data coming from CCD in such a way that 1/2 or 3/4 of pixel data is ignored.
     unsigned ccd_size_divisor = 1;
@@ -343,7 +339,6 @@ void serialize(Stream& str, ScanSession& x)
     serialize(str, x.params);
     serialize_newline(str);
     serialize(str, x.computed);
-    serialize(str, x.hwdpi_divisor);
     serialize(str, x.ccd_size_divisor);
     serialize(str, x.optical_resolution);
     serialize(str, x.optical_pixels);
diff --git a/backend/genesys/tables_sensor.cpp b/backend/genesys/tables_sensor.cpp
index 79f7f7e8d..92250c18b 100644
--- a/backend/genesys/tables_sensor.cpp
+++ b/backend/genesys/tables_sensor.cpp
@@ -104,11 +104,6 @@ inline unsigned get_ccd_size_divisor_gl124(const Genesys_Sensor& sensor, unsigne
     return 1;
 }
 
-inline unsigned default_get_hwdpi_divisor_for_dpi(const Genesys_Sensor& sensor, unsigned xres)
-{
-    return sensor.optical_res / default_get_register_hwdpi(sensor, xres);
-}
-
 StaticInit<std::vector<Genesys_Sensor>> s_sensors;
 
 void genesys_init_sensor_tables()
@@ -136,7 +131,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -160,7 +154,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -184,7 +177,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -210,7 +202,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 2.38f, 2.35f, 2.34f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
 
     {
@@ -336,7 +327,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 2.1f, 2.1f, 2.1f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
 
     {
@@ -433,7 +423,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 2.1f, 2.1f, 2.1f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
 
     {
@@ -533,7 +522,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -565,7 +553,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 2.1f, 2.1f, 2.1f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
 
     {
@@ -620,7 +607,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
 
     {
@@ -744,7 +730,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -787,7 +772,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -830,7 +814,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -873,7 +856,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -916,7 +898,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -932,7 +913,6 @@ void genesys_init_sensor_tables()
     sensor.exposure = { 0x0000, 0x0000, 0x0000 };
     sensor.gamma = { 2.2f, 2.2f, 2.2f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1036,7 +1016,6 @@ void genesys_init_sensor_tables()
     sensor.gain_white_ref = 200;
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1139,7 +1118,6 @@ void genesys_init_sensor_tables()
     sensor.exposure = { 0x01c1, 0x0126, 0x00e5 };
     sensor.gamma = { 2.2f, 2.2f, 2.2f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1258,7 +1236,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     {
         struct CustomSensorSettings
@@ -1292,7 +1269,6 @@ void genesys_init_sensor_tables()
     sensor.custom_regs = {};
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1473,7 +1449,6 @@ void genesys_init_sensor_tables()
     sensor.custom_regs = {};
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1586,7 +1561,6 @@ void genesys_init_sensor_tables()
     sensor.stagger_config = StaggerConfig{4800, 8};
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = get_sensor_optical_with_ccd_divisor;
-    sensor.get_hwdpi_divisor_fun = [](const Genesys_Sensor&, unsigned) { return 1; };
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1683,7 +1657,6 @@ void genesys_init_sensor_tables()
     sensor.custom_regs = {};
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = get_sensor_optical_with_ccd_divisor;
-    sensor.get_hwdpi_divisor_fun = [](const Genesys_Sensor&, unsigned) { return 1; };
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1839,7 +1812,6 @@ void genesys_init_sensor_tables()
     sensor.custom_regs = {};
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = get_sensor_optical_with_ccd_divisor;
-    sensor.get_hwdpi_divisor_fun = [](const Genesys_Sensor&, unsigned) { return 1; };
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
 
     {
@@ -1962,7 +1934,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -1979,7 +1950,6 @@ void genesys_init_sensor_tables()
     sensor.exposure = { 0x0000, 0x0000, 0x0000 };
     sensor.gamma = { 2.2f, 2.2f, 2.2f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_gl124;
 
     {
@@ -2103,7 +2073,6 @@ void genesys_init_sensor_tables()
     sensor.exposure = { 0x0000, 0x0000, 0x0000 };
     sensor.gamma = { 2.2f, 2.2f, 2.2f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_gl124;
 
     {
@@ -2211,7 +2180,6 @@ void genesys_init_sensor_tables()
     sensor.exposure = { 0x0000, 0x0000, 0x0000 };
     sensor.gamma = { 2.2f, 2.2f, 2.2f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_gl124;
 
     {
@@ -2322,7 +2290,6 @@ void genesys_init_sensor_tables()
     sensor.exposure = { 0x0000, 0x0000, 0x0000 };
     sensor.gamma = { 2.2f, 2.2f, 2.2f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_gl124;
 
     {
@@ -2461,7 +2428,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 
@@ -2509,7 +2475,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
     {
         struct CustomSensorSettings
@@ -2599,7 +2564,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
     {
         struct CustomSensorSettings
@@ -2672,7 +2636,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = get_ccd_size_divisor_exact;
     {
         struct CustomSensorSettings
@@ -2734,7 +2697,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.7f, 1.7f, 1.7f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     {
         struct CustomSensorSettings
@@ -2778,7 +2740,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.7f, 1.7f, 1.7f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     {
         struct CustomSensorSettings
@@ -2840,7 +2801,6 @@ void genesys_init_sensor_tables()
     };
     sensor.gamma = { 1.0f, 1.0f, 1.0f };
     sensor.get_register_hwdpi_fun = default_get_register_hwdpi;
-    sensor.get_hwdpi_divisor_fun = default_get_hwdpi_divisor_for_dpi;
     sensor.get_ccd_size_divisor_fun = default_get_ccd_size_divisor_for_dpi;
     s_sensors->push_back(sensor);
 }