Hi, new user, and this is my first post. But I wanted to share the 3 hours of my life updating an iPhone 3G. I feel proud of myself so I hope this will help someone out there. I know the iPhone 3G is out of date, but I still own one and when I was searching I couldn't find a fix. I am on a Mac, so here goes: I have a iPhone 3G locked to UK O2 network. But I needed it unlocked to use it, so last year I had updated it to 4.1 and the iPad baseband 6.15.00. This works with the software unlock ultrasn0w. But as you will read, 6.15.00 baseband basically prevents you from updating firmware, and has GPS troubles. I pulled it out last night and I wanted to update it to the last supported firmware, 4.2.1 8C148. So I read about redsn0w and musclenerd supporting a baseband downgrade. Great! I downloaded redsn0w 0.9.15b3, the latest one, and followed all the instructions. redsn0w, unselected cydia and battery percentages, selected "downgrade from iPad baseband" and hit run. This is where it started to go downhill. Everything ran, iPhone rebooted, then I get "Searching...." under networks..... Thats when I noticed it. No IMEI, no Wifi, no Bluetooth, no Baseband. Basically every post online that I searched said my radio baseband was corrupted and my chip was screwed. The phone would also slap me in the face by rebooting itself every 3 minutes. I tried running downgrade baseband/install ipad baseband a few more times, downloading ios 4.1 to have redsn0w point to it specifically. All was lost. Until I read a post saying something along the lines of "yes you can upgrade to ipad baseband and then downgrade again to 5.13.00"........fingers crossed..... I restored it to 4.2.1 through itunes. Baseband was back, at 5.15.00. However as if to taunt me, everything was restored, but redsn0w still won't install ipad baseband. Tried many times, followed the instructions precisely, but no go. I still need my unlock! Then I remembered a few years ago I had to try different versions of pwnage tool and snowbreeze. So that set off some thoughts, downloaded 0.9.14b2..... iPad baseband installed, iPad baseband downgraded. I am happy, everything works as it should now and I am on a better baseband with GPS. tl;dr Corrupted my 3G baseband, restored in itunes, tried a previous version of redsn0w, fixed 3G BB, upgraded then downgraded iPad BB, and now I have an unlocked 3G. Thanks for reading, and I hope this helps someone in the future.