diff --git a/backend/genesys_devices.c b/backend/genesys_devices.c
index 5ebf4f7f3..afd9dc685 100644
--- a/backend/genesys_devices.c
+++ b/backend/genesys_devices.c
@@ -552,7 +552,7 @@ static Genesys_Motor Motor[] = {
   },
   {MOTOR_HP3670,	/* HP 3670 */
    1200,
-   1200,
+   2400,
    1,
    1,
    {{{
@@ -1069,7 +1069,7 @@ static Genesys_Model hp3670c_model = {
   SANE_FIX (0.0),		/* Amount of feeding needed to eject document 
 				   after finishing scanning in mm */
 
-  0, 12, 24,			/* RGB CCD Line-distance correction in pixel */
+  0, 24, 48,			/* RGB CCD Line-distance correction in pixel */
 
   COLOR_ORDER_RGB,		/* Order of the CCD/CIS colors */
 
diff --git a/backend/genesys_gl646.c b/backend/genesys_gl646.c
index b1ae4d072..ec4bed429 100644
--- a/backend/genesys_gl646.c
+++ b/backend/genesys_gl646.c
@@ -992,9 +992,8 @@ gl646_setup_registers (Genesys_Device * dev,
   stagger = 0;
   if ((!half_ccd) && (dev->model->flags & GENESYS_FLAG_STAGGERED_LINE))
     {
-      /* for CCD_HP3670, stagger happens only at 1200 dpi */
-      if(dev->model->motor_type != MOTOR_HP3670
-      || scan_settings.yres >= dev->sensor.optical_res)
+      /* for CCD_HP3670, stagger happens only at >=1200 dpi */
+      if(dev->model->motor_type != MOTOR_HP3670 || scan_settings.yres >= dev->sensor.optical_res)
         {
           stagger = (4 * scan_settings.yres) / dev->motor.base_ydpi;
         }
@@ -3419,7 +3418,7 @@ setup_for_scan (Genesys_Device * dev, Genesys_Settings settings,
     }
   endx = startx + pixels;
 
-  /* XXX STEF XXX TODO check for pixel width overflow */
+  /* TODO check for pixel width overflow */
 
   /* set up correct values for scan (gamma and shading enabled) */
   status = gl646_setup_registers (dev,
diff --git a/backend/genesys_gl646.h b/backend/genesys_gl646.h
index 8190b8c01..b38bc76b5 100644
--- a/backend/genesys_gl646.h
+++ b/backend/genesys_gl646.h
@@ -446,12 +446,14 @@ static Sensor_Master sensor_master[] = {
   {CCD_HP3670, 300, SANE_TRUE ,  300,  4503, 1200, 4, 42, NULL, SANE_FALSE, 0x33, 0x43},
   {CCD_HP3670, 600, SANE_TRUE ,  600, 10251, 1200, 2, 42, NULL, SANE_FALSE, 0x31, 0x43},
   {CCD_HP3670,1200, SANE_TRUE , 1200, 12750, 1200, 1, 42, NULL, SANE_FALSE, 0x30, 0x43},
+  {CCD_HP3670,2400, SANE_TRUE , 1200, 12750, 1200, 1, 42, NULL, SANE_FALSE, 0x30, 0x43},
   {CCD_HP3670,  75, SANE_FALSE,   75,  4879,  300, 4, 42, NULL, SANE_FALSE, 0x33, 0x43},
   {CCD_HP3670, 100, SANE_FALSE,  100,  4487,  400, 4, 42, NULL, SANE_FALSE, 0x33, 0x43},
   {CCD_HP3670, 150, SANE_FALSE,  150,  4879,  600, 4, 42, NULL, SANE_FALSE, 0x33, 0x43},
   {CCD_HP3670, 300, SANE_FALSE,  300,  4503, 1200, 4, 42, NULL, SANE_FALSE, 0x33, 0x43},
   {CCD_HP3670, 600, SANE_FALSE,  600, 10251, 1200, 2, 42, NULL, SANE_FALSE, 0x31, 0x43},
   {CCD_HP3670,1200, SANE_FALSE, 1200, 12750, 1200, 1, 42, NULL, SANE_FALSE, 0x30, 0x43},
+  {CCD_HP3670,2400, SANE_FALSE, 1200, 12750, 1200, 1, 42, NULL, SANE_FALSE, 0x30, 0x43},
 
   /* HP 2400 master settings */
   {CCD_HP2400,  50, SANE_TRUE ,   50,   675,  200, 4, 42, NULL, SANE_FALSE, 0x3f, 0x02},
@@ -520,18 +522,18 @@ static Motor_Master motor_master[] = {
   /* HP3670 motor settings */
   {MOTOR_HP3670,  75, SANE_TRUE ,  75, FULL_STEP, SANE_FALSE, SANE_TRUE , 1, 200,  3429,  305, 192, 3399, 337, 0.3, 0.4, 192},
   {MOTOR_HP3670, 100, SANE_TRUE , 100, HALF_STEP, SANE_FALSE, SANE_TRUE , 1, 143,  2905,  187, 192, 3399, 337, 0.3, 0.4, 192},
-  {MOTOR_HP3670, 150, SANE_TRUE , 150, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  73,  3429,  305, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670, 300, SANE_TRUE , 300, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  11,  1055,  563, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670, 600, SANE_TRUE , 600, FULL_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 10687, 5126, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670,1200, SANE_TRUE ,1200, FULL_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 15937, 7968, 192, 3399, 337, 0.3, 0.4, 192},
-  {MOTOR_HP3670,2400, SANE_TRUE ,2400, HALF_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 15937, 7968, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670, 150, SANE_TRUE , 150, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  73,  3429,  305, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670, 300, SANE_TRUE , 300, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  11,  1055,  563, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670, 600, SANE_TRUE , 600, FULL_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 10687, 5126, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670,1200, SANE_TRUE ,1200, HALF_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 15937, 6375, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670,2400, SANE_TRUE ,2400, HALF_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 15937, 12750, 192, 3399, 337, 0.3, 0.4, 192},
   {MOTOR_HP3670,  75, SANE_FALSE,  75, FULL_STEP, SANE_FALSE, SANE_TRUE , 1, 200,  3429,  305, 192, 3399, 337, 0.3, 0.4, 192},
   {MOTOR_HP3670, 100, SANE_FALSE, 100, HALF_STEP, SANE_FALSE, SANE_TRUE , 1, 143,  2905,  187, 192, 3399, 337, 0.3, 0.4, 192},
-  {MOTOR_HP3670, 150, SANE_FALSE, 150, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  73,  3429,  305, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670, 300, SANE_FALSE, 300, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  11,  1055,  563, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670, 600, SANE_FALSE, 600, FULL_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 10687, 5126, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670,1200, SANE_FALSE,1200, FULL_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 12751,12751, 192, 3399, 341, 0.3, 0.4, 192},
-  {MOTOR_HP3670,2400, SANE_FALSE,2400, HALF_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 12751,12751, 192, 3399, 341, 0.3, 0.4, 192},
+  {MOTOR_HP3670, 150, SANE_FALSE, 150, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  73,  3429,  305, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670, 300, SANE_FALSE, 300, HALF_STEP, SANE_FALSE, SANE_TRUE , 1,  11,  1055,  563, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670, 600, SANE_FALSE, 600, FULL_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 10687, 5126, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670,1200, SANE_FALSE,1200, HALF_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 15937, 6375, 192, 3399, 337, 0.3, 0.4, 192},
+  {MOTOR_HP3670,2400, SANE_TRUE ,2400, HALF_STEP, SANE_FALSE, SANE_TRUE , 0,   3, 15937, 12750, 192, 3399, 337, 0.3, 0.4, 192},
 
   /* HP2400/G2410 motor settings base motor dpi = 600 */
   {MOTOR_HP2400,  50, SANE_TRUE ,  50, HALF_STEP, SANE_FALSE, SANE_FALSE, 63,  4,  1382,   800,   2, 5400, 5400, 0.25, 0.5, 16},