Preparation :First my already rooted,and use CM10 ROM . 1GB of free space in my SD card. I now use ubuntu 12.04 laptop.
Now get it:
First, we need to download an Arch Linux image for ARM computers here and then copy it to sdcard root
Now ,login to the phone via SSH and go to the root of the sdcard (I use SSHDroid ,Strongly recommended it)
As shown:
All operations in the figure, to follow it . Enjoy youself!!!