One month after upgrading to iOS 4 on an iPhone 3G, the wifi stopped working. It would keep searching endlessly for available networks but never pick up anything.
This happened just before I bought the iPhone 4. It might seem like Apple was trying to push people to upgrade. After all, the iOS 4 upgrade on the iPhone 3G caused it to run unbearably slow.
Next, the wifi was no longer working rendering it’s use limited as an iPod Touch equivalent.
No amount of restoring nor upgrading through the various iOS 4 updates solved the problem. In fact, the wifi problem surfaced just after the extended warranty AppleCare was over. The iPhone 3G worked fine over the two years and never required any repairs till iOS 4.
Here I was with an iPhone 3G that I bought on the official launch day and even spent another $99 on the AppleCare and now it’s a paperweight just after the warranty is over.
So for all you iPhone 3G users out there still on iOS 3, do not upgrade to iOS 4. Not only will it run unbearably slow but it will also cause damage to the wifi hardware.