After trawling the net for two days and finding no answer to my jail breaking problem I have resorted to asking for help, I hope a reader of this forum may have some ideas! I have a jailbroken ipad 1 running a tethered version of 4.3.1. I'm eager to install the untethered version of 5.0.1 which I recently downloaded but every time I try to shift+restore I get the message 'This ipad cannot be restored because of an unknown error '. When I check the apple support pages it suggests it might be a security problem but other than windows firewall (which I've disabled) I don't have any security programs? When googling the problem a lot of pages suggest using iREB. I downloaded this and put it into the necessary state and then retry but get the same message with error 1603?? Does anyone have any ideas, it's so frustrating?