@SteeMan - in case you want to experiment (i.e. not sure if it really works), you might play around with chainloading the g12a-u-boot.bin (s905x2) and sm1-u-boot.bin (s905x3) from https://github.com/hexdump0815/u-boot-misc/releases/tag/200926-01 or gxb-u-boot.bin (s905) or gxl-u-boot.bin (s905x) from https://github.com/hexdump0815/u-boot-misc/releases/tag/200718-01 ... basic chainloading goes like this - https://github.com/hexdump0815/imagebuilder/blob/master/boot/boot-amlogic_gx-aarch64/s905_au