Questions (hypothetical situation)

Yes. You'd lose the 1.59 baseband and it would get upgraded during the restore process. This would be in case you had to take your phone in the Genius Bar for something. If you wanted to restore again using 4.1, then all you would need to do is go through the same process again with tiny umbrella.

Once your phone is unlocked then all you'd need to do is insert your card and it should work normally.

 

I will say that I was JB'd and I restored through iTunes (not using firmware saved on my PC, and did not run TU) prior to taking my iPhone 4 in to the Apple store. For some reason, my 1.59.00 BB was still on the phone after the restore (I selected restore as new iPhone FWIW).

I took the phone to the Apple store for a hardware issue, and they swapped the iPhone out w/out any problems - even though it still had the 1.59.00 BB (perhaps they didn't notice?).

Generally speaking, though - if you want Apple to do anything with your phone, you should restore through iTunes (you shouldn't have my issue - your BB should upgrade to the one that comes w/ 4.1 firmware).

 

I doubt they will go into settings to check if the bb matches the firmware version. You'd be fine.

 

True, but they do hook your iphone up to a diagnostic mac program and that could easily be one of the things they look for.