diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 876bf2b2da..e2801f595f 100644
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -1135,6 +1135,7 @@ static int flash_flag_obsolete(int dev, int fd, off_t offset)
 {
 	int rc;
 	struct erase_info_user erase;
+	char tmp = ENV_REDUND_OBSOLETE;
 
 	erase.start = DEVOFFSET(dev);
 	erase.length = DEVESIZE(dev);
@@ -1146,7 +1147,7 @@ static int flash_flag_obsolete(int dev, int fd, off_t offset)
 		return rc;
 	}
 	ioctl(fd, MEMUNLOCK, &erase);
-	rc = write(fd, &ENV_REDUND_OBSOLETE, sizeof(ENV_REDUND_OBSOLETE));
+	rc = write(fd, &tmp, sizeof(tmp));
 	ioctl(fd, MEMLOCK, &erase);
 	if (rc < 0)
 		perror("Could not set obsolete flag");