diff --git a/gpio-mailbox/Makefile b/gpio-mailbox/Makefile
index eaaee20..1dc26a4 100644
--- a/gpio-mailbox/Makefile
+++ b/gpio-mailbox/Makefile
@@ -29,6 +29,8 @@
   CFLAGS += -DGFIBER_LT
 else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),gflt200)
   CFLAGS += -DGFIBER_LT
+else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),gflt300)
+  CFLAGS += -DGFIBER_LT
 else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),gfmn100)
   CFLAGS += -DWINDCHARGER
 else ifeq ($(BR2_TARGET_GENERIC_PLATFORM_NAME),gfch100)