Hi Darkstar,
I might have accidentally found a solution for GT King Pro kernel panic on mainline kernel. I am now on Manjaro_ARM-VIM3-XFCE release 20.12 but with linux-vim 5.10.1-1 and a new u-boot.ext from LibreElec for_linux-vim-5101.tar — Yandex.Disk . With this new u-boot.ext the kernel panic on GT King Pro with Mainline Kernel 5.10.1-1 seems to be resolved at least so far I have tested where with the old u-boot.ext it always causes kernel panic on GT King Pro. Please do Manjaro arm on Amlogic Tv box?.
Since you have GT King Pro, if you can confirm with this new u-boot.ext from LibreElec also resolved kernel panic on your device and also to try it out on Debian/Ubuntu especially with kernel 5.10 built to see whether it is a universal solution. Look forward to input and new mainline kernel built.