diff --git a/src/stlink-common.c b/src/stlink-common.c
index 69a68ce..f7f03b9 100644
--- a/src/stlink-common.c
+++ b/src/stlink-common.c
@@ -1299,7 +1299,8 @@ int stlink_write_flash(stlink_t *sl, stm32_addr_t addr, uint8_t* base, unsigned
             WLOG("Failed to erase_flash_page(%#zx) == -1\n", addr + off);
             return -1;
         }
-        fprintf(stdout,"\rFlash page at addr: 0x%08lx erased", addr + off);
+        fprintf(stdout,"\rFlash page at addr: 0x%08lx erased",
+		(unsigned long)addr + off);
         fflush(stdout);
         page_count++;
     }
@@ -1472,7 +1473,7 @@ int stlink_write_flash(stlink_t *sl, stm32_addr_t addr, uint8_t* base, unsigned
             if (sl->verbose >= 1) {
                 /* show progress. writing procedure is slow
                    and previous errors are misleading */
-                fprintf(stdout, "\r%3u/%lu pages written", write_block_count++, len/sl->flash_pgsz);
+	      fprintf(stdout, "\r%3u/%lu pages written", write_block_count++, (unsigned long)len/sl->flash_pgsz);
                 fflush(stdout);
             }
         }