diff --git a/backend/genesys/gl843.cpp b/backend/genesys/gl843.cpp
index 83db07565..24594d458 100644
--- a/backend/genesys/gl843.cpp
+++ b/backend/genesys/gl843.cpp
@@ -402,11 +402,11 @@ gl843_init_registers (Genesys_Device * dev)
     // STEPSEL[0:1]. Motor movement step mode selection for tables 1-3 in
     // scanning mode.
     // MTRPWM[0:5]. Motor phase PWM duty cycle setting for tables 1-3
-    dev->reg.init_reg(0x67, 0x7f);
+    dev->reg.init_reg(0x67, 0x7f); // MOTOR_PROFILE
     // FSTPSEL[0:1]: Motor movement step mode selection for tables 4-5 in
     // command mode.
     // FASTPWM[5:0]: Motor phase PWM duty cycle setting for tables 4-5
-    dev->reg.init_reg(0x68, 0x7f);
+    dev->reg.init_reg(0x68, 0x7f); // MOTOR_PROFILE
 
     if (dev->model->model_id == ModelId::PLUSTEK_OPTICFILM_7300) {
         dev->reg.init_reg(0x67, 0x80);
@@ -415,17 +415,11 @@ gl843_init_registers (Genesys_Device * dev)
 
     // FSHDEC[0:7]: The number of deceleration steps after scanning is finished
     // (table 3)
-    dev->reg.init_reg(0x69, 0x01);
-    if (dev->model->model_id == ModelId::CANON_8600F) {
-        dev->reg.init_reg(0x69, 64);
-    }
+    dev->reg.init_reg(0x69, 0x01); // MOTOR_PROFILE
 
     // FMOVNO[0:7] The number of acceleration or deceleration steps for fast
     // moving (table 4)
-    dev->reg.init_reg(0x6a, 0x04);
-    if (dev->model->model_id == ModelId::CANON_8600F) {
-        dev->reg.init_reg(0x69, 64);
-    }
+    dev->reg.init_reg(0x6a, 0x04); // MOTOR_PROFILE
 
     // GPIO-related register bits
     dev->reg.init_reg(0x6b, 0x30);
@@ -516,7 +510,7 @@ gl843_init_registers (Genesys_Device * dev)
 
     // VRHOME, VRMOVE, VRBACK, VRSCAN: Vref settings of the motor driver IC for
     // moving in various situations.
-    dev->reg.init_reg(0x80, 0x00);
+    dev->reg.init_reg(0x80, 0x00); // MOTOR_PROFILE
     if (dev->model->model_id == ModelId::CANON_4400F) {
         dev->reg.init_reg(0x80, 0x0c);
     }
@@ -877,22 +871,38 @@ static void gl843_init_motor_regs_scan(Genesys_Device* dev,
     reg->set8(REG_STEPNO, scan_table.steps_count / step_multiplier);
     reg->set8(REG_FASTNO, scan_table.steps_count / step_multiplier);
 
+    if (dev->model->model_id == ModelId::CANON_8600F) {
+        // FIXME: move all models to the 8600F behavior
+        gl843_send_slope_table(dev, STOP_TABLE, scan_table.table, scan_table.steps_count);
+        reg->set8(REG_FSHDEC, scan_table.steps_count / step_multiplier);
+    }
+
     // fast table
     const auto* fast_profile = get_motor_profile_ptr(dev->motor.fast_profiles, 0, session);
     if (fast_profile == nullptr) {
         fast_profile = &motor_profile;
     }
 
-    unsigned fast_yres = sanei_genesys_get_lowest_ydpi(dev);
-    auto fast_table = sanei_genesys_slope_table(dev->model->asic_type, fast_yres, exposure,
-                                                dev->motor.base_ydpi, step_multiplier,
-                                                *fast_profile);
+    MotorSlopeTable fast_table;
 
-    gl843_send_slope_table(dev, STOP_TABLE, fast_table.table, fast_table.steps_count);
+    if (dev->model->model_id == ModelId::CANON_8600F) {
+        fast_table = create_slope_table_fastest(dev->model->asic_type, step_multiplier,
+                                                *fast_profile);
+    } else {
+        unsigned fast_yres = sanei_genesys_get_lowest_ydpi(dev);
+        fast_table = sanei_genesys_slope_table(dev->model->asic_type, fast_yres, exposure,
+                                               dev->motor.base_ydpi, step_multiplier,
+                                               *fast_profile);
+    }
+
+    if (dev->model->model_id != ModelId::CANON_8600F) {
+        // FIXME: move all models to the 8600F behavior
+        gl843_send_slope_table(dev, STOP_TABLE, fast_table.table, fast_table.steps_count);
+        reg->set8(REG_FSHDEC, fast_table.steps_count / step_multiplier);
+    }
     gl843_send_slope_table(dev, FAST_TABLE, fast_table.table, fast_table.steps_count);
     gl843_send_slope_table(dev, HOME_TABLE, fast_table.table, fast_table.steps_count);
 
-    reg->set8(REG_FSHDEC, fast_table.steps_count / step_multiplier);
     reg->set8(REG_FMOVNO, fast_table.steps_count / step_multiplier);
 
     if (motor_profile.motor_vref != -1 && fast_profile->motor_vref != 1) {
diff --git a/backend/genesys/tables_motor.cpp b/backend/genesys/tables_motor.cpp
index 88904175e..806d837dd 100644
--- a/backend/genesys/tables_motor.cpp
+++ b/backend/genesys/tables_motor.cpp
@@ -53,6 +53,8 @@ void genesys_init_motor_tables()
 {
     s_motors.init();
 
+    MotorProfile profile;
+
     Genesys_Motor motor;
     motor.id = MotorId::UMAX;
     motor.base_ydpi = 1200;
@@ -261,10 +263,64 @@ void genesys_init_motor_tables()
     motor.id = MotorId::CANON_8600F;
     motor.base_ydpi = 2400;
     motor.optical_ydpi = 9600;
-    // BUG: this is a fallback slope that was selected previously and preserved for compatibility
-    motor.profiles.push_back({MotorSlope::create_from_steps(44444, 500, 489), StepType::HALF, 0});
-    motor.profiles.push_back({MotorSlope::create_from_steps(54612, 1500, 219),
-                              StepType::QUARTER, 23000});
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(54612, 1500, 219);
+    profile.step_type = StepType::QUARTER;
+    profile.motor_vref = 3;
+    profile.resolutions = { 300, 600 };
+    profile.scan_methods = { ScanMethod::FLATBED };
+    motor.profiles.push_back(std::move(profile));
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(54612, 1500, 219);
+    profile.step_type = StepType::HALF;
+    profile.motor_vref = 2;
+    profile.resolutions = { 1200, 2400 };
+    profile.scan_methods = { ScanMethod::FLATBED };
+    motor.profiles.push_back(std::move(profile));
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(54612, 1500, 219);
+    profile.step_type = StepType::QUARTER;
+    profile.motor_vref = 2;
+    profile.resolutions = { 4800 };
+    profile.scan_methods = { ScanMethod::FLATBED };
+    motor.profiles.push_back(std::move(profile));
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(54612, 1500, 219);
+    profile.step_type = StepType::QUARTER;
+    profile.motor_vref = 2;
+    profile.resolutions = { 300, 600 };
+    profile.scan_methods = { ScanMethod::TRANSPARENCY,
+                             ScanMethod::TRANSPARENCY_INFRARED };
+    motor.profiles.push_back(std::move(profile));
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(54612, 1500, 219);
+    profile.step_type = StepType::HALF;
+    profile.motor_vref = 1;
+    profile.resolutions = { 1200, 2400 };
+    profile.scan_methods = { ScanMethod::TRANSPARENCY,
+                             ScanMethod::TRANSPARENCY_INFRARED };
+    motor.profiles.push_back(std::move(profile));
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(54612, 1500, 219);
+    profile.step_type = StepType::QUARTER;
+    profile.motor_vref = 0;
+    profile.resolutions = { 4800 };
+    profile.scan_methods = { ScanMethod::TRANSPARENCY,
+                             ScanMethod::TRANSPARENCY_INFRARED };
+    motor.profiles.push_back(std::move(profile));
+
+    profile = MotorProfile();
+    profile.slope = MotorSlope::create_from_steps(59240, 582, 1020);
+    profile.step_type = StepType::HALF;
+    profile.motor_vref = 2;
+    motor.fast_profiles.push_back(std::move(profile));
+
     s_motors->push_back(std::move(motor));