I have the iPhone first-gen with ATT.
I traveled to Europe and wanted to use a local sim card.
Maybe I shouldn't have, but I rolled back to 1.3, unlocked and jailbroke my iPhone.
When I come back to the US, I'd like to make everything go back to normal, use the 2.1 firmware, no need for unlock or jailbreak, etc...
Is this easy? Or am I about to "brick" my phone?
Any advice, links, how-tos welcomed.