There is no modified firmware for GTKING II but you can download the official firmware version 0.3.
In the meantime Coreelec released a firmware for GTKING II.
I have tried many times to build a ubuntu/debian version for GTKING II but there is no luck none of them booted properly.
thank you so much
I download and test this firmware
but If I don't like this firmware, is it possible to return to the original firmware?
Do you have the link to download the original firmware?