Hi, I purchased a factory unlock from ebay, and it worked. I just upgraded to ios 6.1 and jailbroke. Now I have the sim card not valid error, and I put in my at&T sim, and things are fine. But I use T-mobile and that sim card is no longer valid. I assume this means that I've lost my allegedly permanent unlock. I thought my # is in the AT&T database, so how did this happen? Any insight would be appreciated.