diff --git a/libmap/Makefile b/libmap/Makefile
index e9e48ea..ffd78f2 100644
--- a/libmap/Makefile
+++ b/libmap/Makefile
@@ -31,7 +31,7 @@ SOURCES = map_bootblock_get_type.c map_bootblock_is_valid.c \
 	  map_set_partition_name.c map_set_partition_type.c map_set_startup.c \
 	  map_write.c map_block0_write.c map_read_sector.c map_checksum.c \
 	  map_write_sector.c map_get_blocksize.c map_init.c map_read_driver.c \
-	  map_write_driver.c
+	  map_write_driver.c map_update_checksum.c
 
 HEADERS = libmap.h
 
diff --git a/libmap/libmap.h b/libmap/libmap.h
index c62bb02..25f401d 100644
--- a/libmap/libmap.h
+++ b/libmap/libmap.h
@@ -188,4 +188,5 @@ extern unsigned short map_checksum(unsigned char *addr, unsigned int length);
 extern unsigned short map_checksum_ATA(unsigned char *addr, unsigned int length);
 extern char *map_read_driver(map_t *map, int driver_number);
 extern int map_write_driver(map_t *map, int driver_number, char *driver);
+extern int map_update_checksum(map_t *map, int driver_number);
 #endif
diff --git a/libmap/map_update_checksum.c b/libmap/map_update_checksum.c
new file mode 100644
index 0000000..87e44e7
--- /dev/null
+++ b/libmap/map_update_checksum.c
@@ -0,0 +1,36 @@
+#include <stdlib.h>
+
+#include "libmap.h"
+
+int map_update_checksum(map_t *map, int driver_number)
+{
+	char *driver;
+	int blocksize;
+	int block;
+	int part;
+	int length, checksum;
+	int ret;
+
+	driver = map_read_driver(map, driver_number);
+	if (driver == NULL)
+		return -1;
+
+	blocksize = map_get_blocksize(map);
+	block = read_long((u_int32_t*)&map->drivers.DrvInfo[driver_number].Block);
+
+	part = map_seek_driver_partition(map, block * blocksize / 512);
+
+	map_read(map, part);
+
+	length = read_long((u_int32_t*)&map->partition.BootSize);
+	checksum = map_checksum((unsigned char*)driver, length);
+	write_long((u_int32_t*)&map->partition.BootCksum, checksum);
+	
+	free(driver);
+
+	ret = map_write(map, part);
+	if (ret != part)
+		return -1;
+
+	return 0;
+}