Completely dead after failed iOS 6 update attempt

After repairing a friend's broken screen iPod touch, the device got the common but fixable "white screen error." (What I mean by this is the screen is completely white, but it is detected in iTunes and makes sounds when locked or plugged into a charger, etc)

I usually restore when this happens and it's fine, but this one got stuck in the "extracting iOS data" status, so I left for a while. When I came back, the iPod wasn't detected in iTunes, and it was unresponsive.

Now it appears to be completely dead. It won't respond when connected to my PC or a charger. It is not detected by my computer or iTunes, and of course trying to enter recovery mode or DFU mode does no good either.

I left it plugged into a charger for a good long while to make sure battery power wasn't an issue. The iPod was bought new by my friend, and never jailbroken. It had iOS 5 on it prior to the restore attempt.

I find it troubling that an iOS update error could completely kill an iPod. Is there anything else I could try?