Checkout Tow-Boot, it's not 100% there yet, but I'm using it to EFI boot nixos on a pinephone, granted it's the Alwinner one, not the rockchip one, but still.
Does it still require DeviceTree or custom images? Because that's what I'm trying to avoid, I want to stick with devices I can load any generic ISO on. So far the only thing in the ARM space I've seen are servers.
