How difficult is it to modify the configurations? I mean, I'm trying to modify them myself right now to compile for AARCH64 on RPi3 and take advantage of the ARMv8 hardware, but I don't know what all needs to be changed or how you've organized all of the settings. I already ran into some problems with Amiberry, but then there's the defconfig files for the Linux kernel as well as a few other little tidbits here and there. I can get busybox/buildroot working without Recalbox just fine, but I really need a map or something to know what modifications would need to be made then I'll go ahead and toss together some config files if you like.