diff --git a/backend/hp4200.c b/backend/hp4200.c
index cd43ee3d8..f2c617ac2 100644
--- a/backend/hp4200.c
+++ b/backend/hp4200.c
@@ -512,7 +512,7 @@ read_available_data (HP4200_Scanner * s, SANE_Byte * buffer,
       buffer += really_read;
       to_read -= really_read;
 #ifdef DEBUG
-      fprintf (stderr, "read %d bytes\n", really_read);
+      fprintf (stderr, "read %zu bytes\n", really_read);
 #endif
     }
   return SANE_STATUS_GOOD;
diff --git a/backend/pixma/pixma_mp150.c b/backend/pixma/pixma_mp150.c
index 4b15c7368..1a91bf38a 100644
--- a/backend/pixma/pixma_mp150.c
+++ b/backend/pixma/pixma_mp150.c
@@ -709,7 +709,7 @@ send_scan_param (pixma_t * s)
 
   if (mp->generation <= 2)
     {
-      PDBG (pixma_dbg (4, "*send_scan_param gen. 1-2 ***** Setting: xdpi=%hi ydpi=%hi  x=%i y=%i  wx=%i ***** \n",
+      PDBG (pixma_dbg (4, "*send_scan_param gen. 1-2 ***** Setting: xdpi=%u ydpi=%u  x=%i y=%i  wx=%i ***** \n",
                            xdpi, ydpi, x-xs, y, wx));
       data = pixma_newcmd (&mp->cb, cmd_scan_param, 0x30, 0);
       pixma_set_be16 (xdpi | 0x8000, data + 0x04);
@@ -731,7 +731,7 @@ send_scan_param (pixma_t * s)
     }
   else
     {
-      PDBG (pixma_dbg (4, "*send_scan_param gen. 3+ ***** Setting: xdpi=%hi ydpi=%hi x=%i xs=%i y=%i  wx=%i h=%i ***** \n",
+      PDBG (pixma_dbg (4, "*send_scan_param gen. 3+ ***** Setting: xdpi=%u ydpi=%u x=%i xs=%i y=%i  wx=%i h=%i ***** \n",
                            xdpi, ydpi, x, xs, y, wx, h));
       data = pixma_newcmd (&mp->cb, cmd_scan_param_3, 0x38, 0);
       data[0x00] = (is_scanning_from_adf (s)) ? 0x02 : 0x01;
diff --git a/sanei/sanei_scsi.c b/sanei/sanei_scsi.c
index 53736ca83..6eef9988d 100644
--- a/sanei/sanei_scsi.c
+++ b/sanei/sanei_scsi.c
@@ -50,6 +50,7 @@
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -3509,7 +3510,7 @@ sanei_scsi_find_devices (const char *findvendor, const char *findmodel,
 	    if (cdm.matches[i].type != DEV_MATCH_PERIPH)
 	      continue;
 	    result = &cdm.matches[i].result.periph_result;
-	    DBG (4, "%s%d on scbus%d %d:%d\n",
+	    DBG (4, "%s%d on scbus%d %d:" PRIu64 "\n",
 		 result->periph_name, result->unit_number,
 		 result->path_id, result->target_id, result->target_lun);
 	    if (cam_compare_inquiry (fd, result->path_id,