Apply defconfig change for selected boot sequence.

- first usb storage first partition ext2, then fat32
- second usb storage first partition ext2, then fat32
- sd/mmc card first partition ext2, then fat32
- nand ubi restore partition
- nand ubi resque partition
- net from tftp server
- net from nfs server

bootscript name bscript.img, placed into /boot directory on any storage