I haven't been paying a lot of attention to this, since I'm still on 3.0.1 with a non-jailbroken 3G phone (I'm waiting for the next generation to JB the 3G) that has tethering thru the Stealth carrier hack, but I was wondering what would happen if I upgraded to 3.1.3. Would I be able to downgrade as easily as I did from 3.1.2 to 3.0.1 (I simply put the phone in DFU mode restore from a 3.0.1 ipsw and use QuickPwn to get out of the resulting error and then use the Stealth carrier .ipcc file)? In other words, could I use the same procedure, if for some reason I wanted to upgrade to 3.1.3 just for grins? It's hard to search for this, since you only get 3GS threads looking for 3G. Perhaps, it's been discussed, but I haven't seen it.