[bpye]

For completeness sake - uboot can also boot EFI binaries, though upstream won’t support GOP video on RK3588, and is also device tree only so no Windows, just Linux and BSDs.

https://docs.u-boot.org/en/latest/develop/uefi/uefi.html

[iod]

U-Boot does actually have some support for GOP Video¹. It's rather new, so it might be worth revisiting with your specific devices.

¹ https://u-boot.org/blog/seeing-is-believing-video-support-la...