diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 8b487f6..5f16942 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -393,7 +393,7 @@
 static void _fdt_packblocks(const char *old, char *new,
 			    int mem_rsv_size, int struct_size)
 {
-	int mem_rsv_off, struct_off, strings_off;
+	uint32_t mem_rsv_off, struct_off, strings_off;
 
 	mem_rsv_off = FDT_ALIGN(sizeof(struct fdt_header), 8);
 	struct_off = mem_rsv_off + mem_rsv_size;