I think it is OK, but I want to make sure. I have a Pwned 3GS with old boot rom SHSH blobs saved back to 3.0 I have a custom 3.1.2 firmware and have made a 4.0 as well. I really want to tether but I only need it from time to time. I am considering going to 4 just to play around then if MyWi or tethering isn't hacked by the time I need it, rolling back to 3.1.2 Other than being time consuming is this practical? Second part of question. My wife's phone is exactly the same, except her saved blob is only 3.1.3. I guess the risk there is if it bricks she has to go to 3.1.3, is that right? Or once it is pwned is it a safe bet that I can get that custom firmware off of my computer and onto her device? Thanks for your help and this great resource of knowledge.