diff --git a/sst49lf040.c b/sst49lf040.c
index f19b91e..377b74f 100644
--- a/sst49lf040.c
+++ b/sst49lf040.c
@@ -35,7 +35,7 @@
         int i;
         int total_size = flash->total_size * 1024;
         int page_size = flash->page_size;
-        volatile char *bios = flash->virt_addr;
+        volatile uint8_t *bios = flash->virt_addr;
 
         for (i = 0; i < total_size / page_size; i++) {
 		/* Chip erase only works in parallel programming mode
@@ -45,12 +45,12 @@
 	return 0;
 }
 
-int write_49lf040(struct flashchip *flash, unsigned char *buf)
+int write_49lf040(struct flashchip *flash, uint8_t *buf)
 {
 	int i;
 	int total_size = flash->total_size * 1024;
 	int page_size = flash->page_size;
-	volatile char *bios = flash->virt_addr;
+	volatile uint8_t *bios = flash->virt_addr;
 
 	printf("Programming Page: ");
 	for (i = 0; i < total_size / page_size; i++) {