diff --git a/src/common.c b/src/common.c
index 90725c6..011bc08 100644
--- a/src/common.c
+++ b/src/common.c
@@ -611,9 +611,9 @@ int stlink_load_device_params(stlink_t *sl) {
 
     ILOG("Device connected is: %s, id %#x\n", params->description, chip_id);
     // TODO make note of variable page size here.....
-    ILOG("SRAM size: %#x bytes (%d KiB), Flash: %#x bytes (%d KiB) in pages of %zd bytes\n",
+    ILOG("SRAM size: %#x bytes (%d KiB), Flash: %#x bytes (%d KiB) in pages of %u bytes\n",
             sl->sram_size, sl->sram_size / 1024, sl->flash_size, sl->flash_size / 1024,
-            sl->flash_pgsz);
+	 (unsigned int)sl->flash_pgsz);
     return 0;
 }
 
@@ -1445,7 +1445,7 @@ int stlink_verify_write_flash(stlink_t *sl, stm32_addr_t address, uint8_t *data,
         stlink_read_mem32(sl, address + (uint32_t) off, aligned_size);
 
         if (memcmp(sl->q_buf, data + off, cmp_size)) {
-            ELOG("Verification of flash failed at offset: %zd\n", off);
+	  ELOG("Verification of flash failed at offset: %u\n", (unsigned int)off);
             return -1;
         }
     }
@@ -1608,7 +1608,7 @@ int stlink_write_flash(stlink_t *sl, stm32_addr_t addr, uint8_t* base, uint32_t
         for(off = 0; off < len;) {
             size_t size = len - off > 0x8000 ? 0x8000 : len - off;
 
-            printf("size: %zu\n", size);
+            printf("size: %u\n", (unsigned int)size);
 
             if (stlink_flash_loader_run(sl, &fl, addr + (uint32_t) off, base + off, size) == -1) {
                 ELOG("stlink_flash_loader_run(%#zx) failed! == -1\n", addr + off);
@@ -1677,8 +1677,9 @@ int stlink_write_flash(stlink_t *sl, stm32_addr_t addr, uint8_t* base, uint32_t
                 fprintf(stdout, "\r");
 
             if ((off % sl->flash_pgsz) > (sl->flash_pgsz -5)) {
-                fprintf(stdout, "\r%3zd/%3zd pages written",
-                        off/sl->flash_pgsz, len/sl->flash_pgsz);
+                fprintf(stdout, "\r%3u/%3u pages written",
+                        (unsigned int)(off/sl->flash_pgsz),
+			(unsigned int)(len/sl->flash_pgsz));
                 fflush(stdout);
             }
 
diff --git a/src/flash_loader.c b/src/flash_loader.c
index eee9618..2939af9 100644
--- a/src/flash_loader.c
+++ b/src/flash_loader.c
@@ -263,7 +263,7 @@ int stlink_flash_loader_run(stlink_t *sl, flash_loader_t* fl, stm32_addr_t targe
     int i = 0;
     size_t count = 0;
 
-    DLOG("Running flash loader, write address:%#x, size: %zd\n", target, size);
+    DLOG("Running flash loader, write address:%#x, size: %u\n", target, (unsigned int)size);
     // FIXME This can never return -1
     if (write_buffer_to_sram(sl, fl, buf, size) == -1) {
         // IMPOSSIBLE!
diff --git a/src/tools/gui/stlink-gui.c b/src/tools/gui/stlink-gui.c
index a56a2c3..535f9bb 100644
--- a/src/tools/gui/stlink-gui.c
+++ b/src/tools/gui/stlink-gui.c
@@ -460,7 +460,7 @@ dev_format_chip_id (guint32 chip_id)
 static gchar *
 dev_format_mem_size (gsize flash_size)
 {
-    return g_strdup_printf ("%zu kB", flash_size / 1024);
+  return g_strdup_printf ("%u kB", (unsigned int)(flash_size / 1024));
 }
 
 
diff --git a/src/tools/info.c b/src/tools/info.c
index 0d0b823..d3a3151 100644
--- a/src/tools/info.c
+++ b/src/tools/info.c
@@ -49,8 +49,10 @@ static void stlink_print_info(stlink_t *sl)
     printf("openocd: ");
     stlink_print_serial(sl, true);
 
-    printf("  flash: %zu (pagesize: %zu)\n", sl->flash_size, sl->flash_pgsz);
-    printf("   sram: %zu\n",       sl->sram_size);
+    printf("  flash: %u (pagesize: %u)\n",
+	   (unsigned int)sl->flash_size, (unsigned int)sl->flash_pgsz);
+
+    printf("   sram: %u\n",       (unsigned int)sl->sram_size);
     printf(" chipid: 0x%.4x\n",    sl->chip_id);
 
 	params = stlink_chipid_get_params(sl->chip_id);
@@ -65,7 +67,7 @@ static void stlink_probe(void)
 
     size = stlink_probe_usb(&stdevs);
 
-    printf("Found %zu stlink programmers\n", size);
+    printf("Found %u stlink programmers\n", (unsigned int)size);
 
     for (size_t n = 0; n < size; n++)
         stlink_print_info(stdevs[n]);
diff --git a/src/tools/term.c b/src/tools/term.c
index c07fcc7..3f3517f 100644
--- a/src/tools/term.c
+++ b/src/tools/term.c
@@ -103,7 +103,7 @@ struct stlinky*  stlinky_detect(stlink_t* sl)
             st->off = sram_base + off;
             stlink_read_mem32(sl, st->off + 4, 4);
             st->bufsize = READ_UINT32_LE(sl->q_buf);
-            printf("stlinky buffer size 0x%zu \n", st->bufsize);
+            printf("stlinky buffer size 0x%u \n", (unsigned int)st->bufsize);
             multiple++;
         }
     }
@@ -283,7 +283,7 @@ int main(int ac, char** av) {
             printf("using stlinky at 0x%x\n", st->off);
             stlink_read_mem32(gsl, st->off + 4, 4);
             st->bufsize = READ_UINT32_LE(gsl->q_buf);
-            printf("stlinky buffer size 0x%zu \n", st->bufsize);
+            printf("stlinky buffer size 0x%u \n", (unsigned int)st->bufsize);
         }else{
             cleanup(0);
         }
diff --git a/src/usb.c b/src/usb.c
index c75476d..6dcd7c9 100644
--- a/src/usb.c
+++ b/src/usb.c
@@ -44,8 +44,8 @@ ssize_t send_recv(struct stlink_libusb* handle, int terminate,
         printf("[!] send_recv send request failed: %s\n", libusb_error_name(t));
         return -1;
     } else if ((size_t)res != txsize) {
-        printf("[!] send_recv send request wrote %d bytes (instead of %d).\n",
-                res, txsize);
+        printf("[!] send_recv send request wrote %u bytes (instead of %u).\n",
+	       (unsigned int)res, (unsigned int)txsize);
     }
 
     if (rxsize != 0) {