You may have read my tale of woe. I updated my iPhone 3G to iOS4, and it went wrong. Hideously wrong.http://hairydalek.posterous.com/my-iphone-ios4-update-woes And I am not alone – Apple’s support forums are reporting similar issues – this update seems to have affected many people. It seems that the “-34” and “files not found” errors I was getting was something to do with the downsampling of music to 128kbs. I did get the phone running, but it’s slow and choppy. I like the folders in iOS4, and I had started to organise my apps into folders. However, given the limited features for 3G users, this seems to be an update to get iAds out to as many people as possible (I am dreadfully cynical about advertising). The other problem was speed. The iPhone is dreadfully unresponsive. Apps take for ever to start up. The soft keyboard is very choppy and unresponsive, and in Twitter for iPhone takes forever to appear. I took the decision yesterday to downgrade to 3.1.3. I know this is dangerous, and I could have a non functioning phone at the end of it, but I though I’d bite the bullet. The instructions here seem to be pretty easy to follow. http://www.maclife.com/article/howtos/downgrade_iphone_os_40_beta_back_iphone… And indeed they were – after a little fiddling with iTunes, and the Terminal, I got my iPhone 3G back to 3.1.3. It synced it’s apps, and a quick test showed me that it is indeed snappier, faster and more responsive that it was running iOS4. The Twitter for iPhone app starts up more quickly, and typing on the keyboard is far more pleasurable. The bonus was that my in app data, which I had thought was gone for good, was restored. I used one of the backups taken during my attempted recovery process (just because I thought it may contain some useful data), and it appears that data stored in apps, which I lost during the iOSX 4 process, has been restored. Maybe I could have used those backups for iOS 4 too after all. Now, as stated, reverting your iPhone is potentially dangerous. The method I linked to seems to have worked for me, but this is no guarantee that they will restore your phone. Use it at your own risk. The same applies to any hack of this nature. Thanks to MacFormat dude @chrisphin for Tweeting this fix the other day.