Here you can find how to patch aufs. We use this method to make berryboot work.
tony_zhang Posted at 2014-8-10 01:48
Thanks for the tip! I've bookmarked that page for future references, as I'm not in fit shape to deal with it right away, having spent most of the last 24 hours on various experiments with the Banana Pi.
I did find out what to do with the bootloader files I compiled earlier, and have inserted the "sunxi-spl.bin" and "u-boot.img" files into a copy of the cubieboard2 berryboot image, at offsets 0x2000 and 0xA000 respectively, as specified in sunxi documents. This did affect the boot procedure visibly (faster and with different LED effects), but I was still never able to make berryboot access USB drives, which is crucial. It is only through USB drives that we can access customized OS images to install, since all the ones on the online site must be assumed incompatible. And for optimum use of berryboot it would also be best to install the OS images to a USB drive, so as not to be limited by the SD card sizes.
After spending half the night on various berryboot experiments I started using its console mode to check the realtime contents of the filesystem, and compared those findings with some of the berryboot source code, at which point I realized that the way berryboot looks for USB devices doesn't match how the kernel I compiled works. It does detect the USB drives, but doesn't register them as /sys/class/block devices, which is the only thing berryboot checks for in searching for USB drives. So that is the point where I gave up (for now).
Hopefully the link you provided will inform me on how to make a home-compiled kernel work like berryboot expects it to do, so that I can make berryboot access USB drives (just like it always could on Raspberry Pi).
Best regards: dlanor