diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c
index c05487cf..c09ecd85 100644
--- a/util/nvmutil/nvmutil.c
+++ b/util/nvmutil/nvmutil.c
@@ -1850,7 +1850,7 @@ rw_file_exact(int fd, u8 *mem, size_t nrw,
 		}
 
 		/* Prevent theoretical overflow */
-		if (rv > nrw - rc)
+		if ((size_t)rv > nrw - rc)
 			goto err_rw_file_exact;
 
 		rc += (size_t)rv;