diff --git a/tools/imx8image.c b/tools/imx8image.c
index 133780f..fa8f227 100644
--- a/tools/imx8image.c
+++ b/tools/imx8image.c
@@ -365,7 +365,7 @@
 	struct stat sbuf;
 	unsigned char *ptr;
 	int tail;
-	int zero = 0;
+	uint64_t zero = 0;
 	uint8_t zeros[4096];
 	int size, ret;
 
diff --git a/tools/imx8mimage.c b/tools/imx8mimage.c
index 9985b95..11e40cc 100644
--- a/tools/imx8mimage.c
+++ b/tools/imx8mimage.c
@@ -248,7 +248,7 @@
 	struct stat sbuf;
 	unsigned char *ptr;
 	int tail;
-	int zero = 0;
+	uint64_t zero = 0;
 	uint8_t zeros[4096];
 	int size, ret;