Hi, I've intentionally kept my iphone to version 3.0 (iTunes is still 8.2) to take advantage of the unsigned tethering carrier file. Anyway, my volume key fell off and it's still under warranty. I brought my phone in and they offered to replace the entire thing. This would likely give me a refurbished phone with 3.1.3 firmware. A) Any possibility of downgrading to 3.0, then restoring 3.0 backup? B) Will 3.0 backup work with a 3.1.3 phone? C) Or should I just upgrade my phone to 3.1.3, update the backup, then do the warranty replacement? And kiss tethering goodbye? Thanks for your help. 30 minutes of searching around and I couldn't find anything specific to what I have, though it does appear that 3.1.3 downgrading is almost entirely out of the question unless you have a certain model/baseband/something?