Troubleshooting USB Key Creation
If you're reading this page it's because your AppleTV box will not boot from the SwissArmyKnife USB you created. The AppleTV is a little fussy about USB keys and there is no magic brand of key that is best to use; if you buy two identical USB drives of the same size and same brand you may find one of them works and the other doesn't. If the USB key didn't work please try the following steps. If they don't make a difference, please try again with a different USB key.
The AppleTV does not automatically boot from a USB key when it is connected unless the recovery boot process has been invoked at least once. If you have a virgin AppleTV you will need to force the recovery boot process by pressing and holding the menu and - keys on the Apple remote for 5-10 seconds as the system is turned on.
Zero the contents of the USB drive
It may help to "zero out" the USB key to remove all traces of old partitions. This is similar to a secure wipe of the drive and is done by writing 0's to every block.
Mac OS X users can use this command, where /dev/disk1 is the USB key:
dd if=/dev/zero of=/dev/rdisk1 bs=1m
Linux users can use this command, where /dev/sdb is the USB key:
dd if=/dev/zero of=/dev/sdb bs=1M
Windows users can download the http://chewitt.openelec.tv/bignothing.img.zip file. This is a 4.1GB file of 0's (compressed to 4MB for downloading). Use "USB Image Tool" to restore this to a 4GB (or smaller) USB drive using device mode and the "ignore image sizes" and "truncate oversize images" settings.
Once you've zero'd the drive you can re-create the SwissArmyKnife USB and try booting the AppleTV again.
If you're still stuck, or there is strange stuff appearing on screen you'll be wanting to post a question to the forum support thread. If you post a question to the forums please think about clearly describing the steps taken so far, and if there is weird text on screen you don't understand please snap a pic using a camera or smartphone, upload to a picture sharing site and share the URL - a picture often speaks a thousand words when we're trying to understand what may have gone wrong.