diff --git a/backend/genesys_gl843.c b/backend/genesys_gl843.c
index 81e5a2459..9ac13d09d 100644
--- a/backend/genesys_gl843.c
+++ b/backend/genesys_gl843.c
@@ -1262,7 +1262,7 @@ gl843_init_optical_regs_scan (Genesys_Device * dev,
   dpiset = used_res * cksel;
 
   /* start and end coordinate in optical dpi coordinates */
-  startx = (start + dev->sensor.dummy_pixel+dev->sensor.black_pixels)/cksel;
+  startx = (start + dev->sensor.dummy_pixel)/cksel;
   used_pixels=pixels/cksel;
   endx = startx + used_pixels;
 
@@ -2430,9 +2430,9 @@ gl843_slow_back_home (Genesys_Device * dev, SANE_Bool wait_until_home)
 			SCAN_FLAG_IGNORE_LINE_DISTANCE);
 
   /* set exposure to zero */
-  sanei_genesys_set_triple(local_reg,REG_EXPR,0);
-  sanei_genesys_set_triple(local_reg,REG_EXPG,0);
-  sanei_genesys_set_triple(local_reg,REG_EXPB,0);
+  sanei_genesys_set_double(local_reg,REG_EXPR,0);
+  sanei_genesys_set_double(local_reg,REG_EXPG,0);
+  sanei_genesys_set_double(local_reg,REG_EXPB,0);
   
   /* clear scan and feed count */
   RIE (sanei_genesys_write_register (dev, REG0D, REG0D_CLRLNCNT | REG0D_CLRMCNT));
@@ -3239,10 +3239,10 @@ gl843_offset_calibration (Genesys_Device * dev)
   lines=1;
   bpp=8;
 
-  /* comptue divider factor to compute final pixels number */
+  /* compute divider factor to compute final pixels number */
   dpihw=sanei_genesys_compute_dpihw(dev,dev->settings.xres);
   factor=dev->sensor.optical_res/dpihw;
-  resolution=dev->settings.xres;
+  resolution=dpihw;
   pixels = dev->sensor.sensor_pixels/factor;
   black_pixels = dev->sensor.black_pixels / factor;
   DBG (DBG_io, "gl843_offset_calibration: dpihw       =%d\n", dpihw);
diff --git a/backend/genesys_gl843.h b/backend/genesys_gl843.h
index aa0e18430..bc41448e2 100644
--- a/backend/genesys_gl843.h
+++ b/backend/genesys_gl843.h
@@ -559,7 +559,7 @@ typedef struct {
  * database of sensor profiles
  */
 static Sensor_Profile sensors[]={
-	{CCD_KVSS080,  600,  8000, 0x000000, 0x00ffff, 0x03ffff, 5168, 0, 0x2a, 0, 0, 0, 0x00, 0x00, 0x0a, 0x20, 0x21},
+	{CCD_KVSS080,  600,  8000, 0x000000, 0x00ffff, 0x03ffff, 5168, 0, 0x2a, 0, 0, 0, 0x00, 0xc0, 0x00, 0x00, 0x00},
 	{CCD_G4050  ,  600,  8016, 0x0001ff, 0x03ffff, 0x03ffff, 5168, 0, 0x2a, 0, 0, 0, 0x00, 0x40, 0x00, 0x5a, 0x00},
 	{CCD_G4050  , 1200, 56064, 0x03ffff, 0x0001ff, 0x0001ff, 5168, 0, 0x2a, 0, 0, 0, 0x11, 0x40, 0x00, 0x5f, 0xc0},
 	{CCD_G4050  , 2400, 56064, 0x03ffff, 0x000000, 0x000000, 5168, 0, 0x2a, 0, 0, 0, 0x11, 0x40, 0x00, 0x5f, 0xc0},