Cook lightmap for ANDROID_ETC2

I’m developing a mobile game using Unreal engine 4.22.

I can see HQ and LQ lightmap in the worldsetting. But i only need LQ. I wan’t cook HQ lightmap for mobile, in order to reduce the size of the game package.
I know how to reencode LQ or HQ lightmap to delete lightmap’s information, and HQ lightmap wan’t be used in Mobile Shader.

So that’s my question: How can i remove HQ lightmap information in Map Build Data Registry, or not cook HQ out.
Thanks guys!