3GS @4.2.1 inexplicably crashed. Now Unknown IMEI & ICCID
I successfully upgraded my 3GS (AT&T, old bootrom, 5.13.04, Pwnagtool, ultrasn0w) a couple of weeks ago. Today, while listening to a podcast while running a GPS app, the phone inexplicably crashed. COMPLETELY. Now I get a USB icon with a "Restore Needed" message and the "i" button on the lower right of the screen reports:IMEI unknown, ICCID unknown. I doubt I'll ever figure out why this happened but what do I do to restore it? 1) Do I merely option+Restore in iTunes (and select the custom 4.2.1 IPSW I built a couple of weeks ago or 2) should I go through a complete Pwnagtool build, Pwnag DFU mode and reinstall the whole system from backup?
Thanks in advance,