diff --git a/bootinfo.c b/bootinfo.c
index 6fbd15c..7f6fd34 100644
--- a/bootinfo.c
+++ b/bootinfo.c
@@ -125,7 +125,7 @@ typedef struct _boot1_private_head_t {
     __u32 work_mode;
     __u32 storage_type;
     normal_gpio_cfg storage_gpio[32];
-    char storage_data[256];
+    __u8 storage_data[256];
 } boot1_private_head_t;
 
 typedef struct _boot1_file_head_t {