1) A custom recovery.fstab, such as those containing an /sdcard symlinked to /data/media.
/sdcard datamedia /dev/null
# more recovery.fstab entries here
2) A custom graphics.c, such as those which may have non-aosp framebuffer format
3) And if it Performs any device specific initialization using the postrecoveryboot.sh script.
If our device requires or has those can you give me the download links?