Hey everyone,

So something strange happened to me earlier today. I was on my jailbroken and unlocked iPhone 4 with 4.0.1 OS\FW: 01.59.00 and a message popped up that said "SIM Failure." So I rebooted the phone and it was back to normal.

Later this afternoon I was on it again and the signal just dropped. So I rebooted it again and it went into a restore mode loop(with the iTune sign and a the USB cable below it.) I had to restore the phone back to factory settings. I used the following ipsw file 'iPhone3,1_4.0.1_8A306_Restore.ipsw' to restore the phone. Once that was done, I get into the phone by connecting it to my computer and iTunes. Then I connected the phone to my WIFI.

Then it was jailbroken with JailbreakMe. Once that was done I went into cydia and installed 'ultrasn0w'. After that, whenever I would reboot my phone the signal would disappear. I would have to put the AT&T sim card in then reboot the phone and put my T-Mobile card back in and it would work.

I have restored the phone again and jailbroke it but it is still doing the same thing. I also noticed after jailbraking and unlocking the phone. My "Cellular Data Network" option was missing from (Settings > General > Network > Cellular Data Network.) Which means that I can't setup my T-Zone settings and MMS settings. I was also able to see all the AT&T settings under 'Phone' option in Settings. It almost seems like the phone isn't unlocked, but it works every once in a while.

Any help would be greatly appreciated. I hope I can get this resolved by tomorrow. I need my phone for work and since the SIM is cut to fit the micro SIM. I can't use another phone.

Thanks in advance!