Recovering the method of Grub2 covered by Win 8 boot

We will be covered after installing Windows 8 grub, tried a lot of methods are useless, I use the Grub command line in the PE CD can not recognize the Linux partition The file shows that it is all garbled. Had to be a bootable USB flash drive for Grub2.
First you need a Linux system to install Grub2 on a USB stick. I temporarily installed Ubuntu 12.04 in the virtual machine because there is just a mirror on hand.
First make sure your U disk can boot from MBR, not sure you can format it under Linux, choose MBR mode, I use Ubuntu that comes with the formatting tool.
Note that you must unmount before formatting.
New partition after formatting.
Then execute sudo grub-install --boot-directory=/media/u --recheck /dev/sdb
u is the name of the mount folder, sdb is the device name.
No error return is the installation is complete.
Then restart the computer to boot from the U disk will enter the Grub command line.
Grub2 and Grub's orders are different, you can go and see for yourself. I won't say it.
According to the information found online, I set the root and load the kernel with linux, load the memory disk with initrd and then boot. . . .
It's a pity that it shouldn't work. At this time, it should be Linux in the memory disk. It is not Ubuntu on the disk. I don't know. I hope the master knows why this is not the case.
The information on the Internet may be old, and you can only rely on yourself. Turned over the Grub2 manual and found the normal [FILE] command, which is to load the Grub2 menu.
This is easy to do, as long as the original boot menu is loaded, it should be properly guided.
set root=(hd0,4)
normal /boot/grub/grub.cfg
Then you will come out with the familiar Grub boot menu!