diff --git a/libmap/Makefile b/libmap/Makefile
index 9370a43..e9e48ea 100644
--- a/libmap/Makefile
+++ b/libmap/Makefile
@@ -30,7 +30,8 @@ SOURCES = map_bootblock_get_type.c map_bootblock_is_valid.c \
 	  map_set_bootinfo.c map_set_driver_info.c map_set_driver_number.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_sector.c map_get_blocksize.c map_init.c map_read_driver.c \
+	  map_write_driver.c
 
 HEADERS = libmap.h
 
diff --git a/libmap/libmap.h b/libmap/libmap.h
index 2335288..c62bb02 100644
--- a/libmap/libmap.h
+++ b/libmap/libmap.h
@@ -187,4 +187,5 @@ extern int map_get_blocksize(map_t *map);
 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);
 #endif
diff --git a/libmap/map_write_driver.c b/libmap/map_write_driver.c
new file mode 100644
index 0000000..0326875
--- /dev/null
+++ b/libmap/map_write_driver.c
@@ -0,0 +1,30 @@
+#include <stdlib.h>
+
+#include "libmap.h"
+
+/* the size information in DrvInfo must be the same as the driver size in memory */
+
+int map_write_driver(map_t *map, int driver_number, char *driver)
+{
+	int block, size;
+	int blocksize;
+	int ret;
+
+	if (driver == NULL)
+		return -1;
+
+	if (!map_is_valid(map))
+		return -1;
+
+	blocksize = map_get_blocksize(map);
+
+	if (driver_number > map_get_driver_number(map))
+		return -1;
+
+	block = read_long((u_int32_t*)&map->drivers.DrvInfo[driver_number].Block);
+	size = read_short((u_int16_t*)&map->drivers.DrvInfo[driver_number].Size);
+
+	ret = map->device->write_sector(map->device->data, block, driver, size * blocksize);
+
+	return ret;
+}