diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c
index e0f3dfc98e06b784132a73e1e715b69592b00adf..7daf16499aa65440e41544e0f93f0226640ab91a 100644
--- a/drivers/misc/cros_ec.c
+++ b/drivers/misc/cros_ec.c
@@ -827,6 +827,9 @@ int cros_ec_flash_write(struct udevice *dev, const uint8_t *data,
 	uint32_t end, off;
 	int ret;
 
+	if (!burst)
+		return -EINVAL;
+
 	/*
 	 * TODO: round up to the nearest multiple of write size.  Can get away
 	 * without that on link right now because its write size is 4 bytes.