Hello. I have a 32 GB iPhone 3Gs that is currently jailbroken and unlocked on iOS 4.3.5. This was performed a couple years ago by upgrading the baseband to the iPad 06.15. Earlier today I successfully downgraded that baseband to version 05.13.04 to restore GPS functionality. So, thinking today was my lucky day, I tried to upgrade to iOS 6.1.3 (I don't have SHSH blobs for any earlier versions of iOS 6). I follow the instructions on iClarified to to the work, selecting the 6.1.3 IPSW and requesting the baseband not be upgraded, but the initial Restore operation always fails with a message saying "Couldn't Restore, unexpected error (2831)." Fortunately, the phone retains it's current iOS 4.3.5 & baseband 05.13.04 state, and seems to be working fine. So, anybody know what the error 2831 means? Are there more reliable instructions than those on iClarified (I've had very good luck with them in the past). My iTunes version is: 11.0.2. Thanks in advance for your help.