Installing OpenWrt fork firmware

Ok just briefly, I saw some differences.
I need some time to test it out.

Note Please ignore the 2nd picture, it is a known problem.

Questions:

  1. MU-MIMO option - I thought this was enabled by default? There is no such settings in OpenWrt.
  2. Enable 256-QAM = 802.11n 2.4GHz Only --> This setting is shown in WLAN1 (5GHz Radio) --> bug??