How to extract kernel config from uImage
1. get extract-ikconfig in kernel-source/scripts/
$mkdir extreact-uImage
$cd extreact-uImage
$cp {kernel-source}/scripts/extract-ikconfig .
2. dump uImage skip 1024 bytes
$cp {uImage/what/you/want} uImage
$dd if=uImage of=dd_uImage bs=1024 skip=1
$./extract-ikconfig dd_uImage > config
