Can I apply the update 5.40.03 to B6T (India, Australia version)
It is still possible to downgrade to 04.31.25 for B6 EU model or 04.31.20 for US model from the latest 05.31.xx FW. To do so, ge the 05.40.xx FW first.
The reason this works is that the 05.40.03 is a beta an untested fw which is also unlocked so that means we can go down in FW downgrade. If you directly try to downgrade from official 05.31.xx to 04.31.xx then it will not work because LG has made a lock on the firmware it self.
Download this one first
Then use the LGTV_UPDATER procedure (google it) to upgrade to 05.40.03. Only then you will be able to downgrade to 04.31.25.
04.31.25 (EU version, to get the US version just google it)
After downgrade, reset the TV and get better performance, black levels as they should have been and increased HDR game mode brightness aswell as other modes. You will lose HLG and maybe some other not important things, but who cares if you only game, watch DV/HDR content on the 2016 OLED TV