How to make Windows PE boot from USB Thumb drive...
crosspost from http://blogs.msdn.com/rextang
The story was as follows...
I bought a Ultra Mobile PC (should be a small tablet-pc since it still got keyboard) with Windows Vista Home Premium installed. The vendor didn't provide Recovery disk. Right after I got the PC, I upgraded the OS to Vista Ultimate, the upgrade was smoothly and I didn't notice the minor changes on the F8 boot menu. I was pretty happy with this Vista Ultimate UMPC until I found another one that's more smaller than this one. I bought the small one too and was deciding to sell the larger one, and was thinking to do a hard disk full recovery back to factory-out status.
By the manual it's possible to do a full recovery via Vista Start-up menu (by pressing F8 on start-up). there will be a vendor-defined recovery menu item lead to the recovery. by now it comes to the problem. after upgrading to Vista Ultimate, the vendor-defined recovery option was disappeared!!! it seems that while upgrading process Vista completely re-org the start-up options...
Since the vendor didn't provide recovery disk, I mailed the vendor asking them to recovery the pc to factory-out status for me. they said that upgrading the machine's OS is out of the warrenty and it would cost me money to recovery the machine even if I am still in the one-year warrenty period, and also need to send the machine back to the company, which will take days to get things done. I was not pretty happy with things like this. (a recovery CD should be a necessity! the new smaller one got it's recovery CD and I can easily recovery the machine while once I failed upgrading the machine to Vista Ultimate!!)
So I was trying to fix this by myself.
Thanks the vendor that they did have all the drivers contained on the hard drive, which also included a directory called EmergencyCD, which contains a ISO file for the emergency CD. I burned the CD out to a CD-ROM and trying to use it to boot up the PC, but it seems that the PC got compatibility problems with my CD-ROM drive and not succeed...
So I was thinking about burning the ISO to a USB pen drive so that it can be bootable from a USB. by searching on the web didn't found any software that is exactly doing the function of taking an ISO image as input and just burn it out to a USB pen drive. fortunately I found this article...
since the EmergencyCD ISO is a vista boot image, it's a standard Windows PE image. at first I was simplely extracting the ISO using WinRAR and just copy the files to USB pen drive. it was obviously that the PC won't boot like this.
later by following the instructions providing by the article to set the USB pen drive bootable, I successfully boot-up the PC by the EmergencyCD image , at the first run to search the problems it found the lost EISA recovery partition and fixed it back, by reboot with the Emergency CD again the vendor-provided disk full recovery menu option showed up!!! bravo!!! it recovered the whole machine to factory-out status by runing cusmized Symantec Ghost program and about 10 more minutes while I was writing this post the machine was back to the status like I just bought it.
For reference I'll also note the steps of making Windows PE bootable USB pen drive here...
[via here]
Preapring Windows PE to Boot from a USB Thumb Drive
These steps will take you through preparing a USB ram drive (thumb drive, pen drive, or how ever you care to refer to it) so that you may use it to boot your Windows PE image without the need of a hard drive (or bootable CD/DVD). These steps assume you have already generated your Windows PE folder structure where you would typically burn it to an ISO image. For preparing your WinPE image, please see Working with Windows PE Images.
1) Run diskpart from command prompt running as administrator (right click the command prompt icon and choose "Run As Administrator")
2) Type the command: list disk to see the available disks and note the one that represents your USB thumb drive
3) Select the disk: select disk # where # is the disk you determined in the above step
4) Now that the proper disk is selected, prepare it with the clean command by typing clean
5) Now create a partition on the clean drive by typing: create partition primary
6) Select the new partition by typing: select partition 1
7) Set the partition as active by typing: active
8) Format the partition as FAT32 by typing: format fs=fat32
9) Assign the new partition by typing: assign
10) Type exit to quit diskpart
Now you are ready to copy the files. The location from which you want to copy the files is the folder created which would normally serve as the contents of your ISO file. For example: c:\images\winpe\iso
Typically this file will contain three folders and a file: directories: boot, EFI, and source. file: bootmgr. Simply copy these files to the prepared USB thumb drive root and you are ready to go!
With the RAM drive inserted, you will either need to go into the computer's BIOS settings at boot up and arrange the boot order to place the USB drive above the system hard drive. Alternatively most systems have a "Boot Menu" keystroke such as F12 which will let you choose the device to which you want to boot
Case closed, ready to sell my umpc now...
FYI.