diff --git a/board/reef/battery.c b/board/reef/battery.c
index 112f15372e..9480dfd548 100644
--- a/board/reef/battery.c
+++ b/board/reef/battery.c
@@ -15,9 +15,8 @@
 #include "i2c.h"
 #include "util.h"
 
-/* Shutdown mode parameter to write to manufacturer access register */
-#define PARAM_CUT_OFF_LOW  0x10
-#define PARAM_CUT_OFF_HIGH 0x00
+#define ELECTRO_SHIP_MODE_REG 0x3a
+#define ELECTRO_SHIP_MODE_DAT 0xC574
 
 /* Battery info for BQ40Z55 */
 static const struct battery_info info = {
@@ -54,21 +53,13 @@ const struct battery_info *battery_get_info(void)
 int board_cut_off_battery(void)
 {
 	int rv;
-	uint8_t buf[3];
 
 	/* Ship mode command must be sent twice to take effect */
-	buf[0] = SB_MANUFACTURER_ACCESS & 0xff;
-	buf[1] = PARAM_CUT_OFF_LOW;
-	buf[2] = PARAM_CUT_OFF_HIGH;
+	rv = sb_write(ELECTRO_SHIP_MODE_REG, ELECTRO_SHIP_MODE_DAT);
+	if (rv != EC_SUCCESS)
+		return rv;
 
-	i2c_lock(I2C_PORT_BATTERY, 1);
-	rv = i2c_xfer(I2C_PORT_BATTERY, BATTERY_ADDR, buf, 3, NULL, 0,
-		      I2C_XFER_SINGLE);
-	rv |= i2c_xfer(I2C_PORT_BATTERY, BATTERY_ADDR, buf, 3, NULL, 0,
-		       I2C_XFER_SINGLE);
-	i2c_lock(I2C_PORT_BATTERY, 0);
-
-	return rv;
+	return sb_write(ELECTRO_SHIP_MODE_REG, ELECTRO_SHIP_MODE_DAT);
 }
 
 enum battery_disconnect_state battery_get_disconnect_state(void)