diff --git a/cmd/onenand.c b/cmd/onenand.c
index 592985a..d633f19 100644
--- a/cmd/onenand.c
+++ b/cmd/onenand.c
@@ -53,7 +53,7 @@
 	if (*size == mtd->size)
 		puts("whole chip\n");
 	else
-		printf("offset 0x%lx, size 0x%x\n", *off, *size);
+		printf("offset 0x%lx, size 0x%zx\n", *off, *size);
 
 	return 0;
 }
@@ -401,7 +401,7 @@
 
 	ret = onenand_block_read(ofs, len, &retlen, (u8 *)addr, oob);
 
-	printf(" %d bytes read: %s\n", retlen, ret ? "ERROR" : "OK");
+	printf(" %zu bytes read: %s\n", retlen, ret ? "ERROR" : "OK");
 
 	return ret == 0 ? 0 : 1;
 }
@@ -428,7 +428,7 @@
 
 	ret = onenand_block_write(ofs, len, &retlen, (u8 *)addr, withoob);
 
-	printf(" %d bytes written: %s\n", retlen, ret ? "ERROR" : "OK");
+	printf(" %zu bytes written: %s\n", retlen, ret ? "ERROR" : "OK");
 
 	return ret == 0 ? 0 : 1;
 }