msftguy

Can't be done (yet) using publicly available exploits. There's a known DFU mode exploit for A4 (and lower) devices, there's nothing (public) yet for the A5. User-mode jailbreaks won't help...

You could try using make_noerase_ipsw.py ( http://code.google.com/p/iphonetunnel-usbmuxconnectbyport/source/browse/trunk/make_noerase_ipsw/make_noerase_ipsw.py ). Just make sure it works on someone else's (backed up) 4S first. It should perform an upgrade mode restore even from DFU...