diff --git a/hikey960.mk b/hikey960.mk
index 1888158..342fa04 100644
--- a/hikey960.mk
+++ b/hikey960.mk
@@ -6,6 +6,9 @@
 TARGET_PREBUILT_DTB := $(LOCAL_KERNEL_HOME)/hi3660-hikey960.dtb
 
 ifndef HIKEY_USES_GKI
+  ## Please check the following link for the android-mainline
+  ## kernel build instructions:
+  ##   https://www.96boards.org/documentation/consumer/hikey/hikey960/build/android-mainline.md.html
   ifeq ($(TARGET_KERNEL_USE), mainline)
     HIKEY_USES_GKI := true
   else