Like most of you out there, I upgraded my iPhone to iOS4 right when it came out. And like most, have hated the upgrade because my iPhone 3g ran like crap afterwords. It was so slow, I could hardly use it at all. Crashes, mega slow, and all sorts of crappy performance issues. Nothing seemed to work. After scouring the Internet, I finally found a couple posts and threads that addressed the issue. What I gathered was that the iOS4 update needs some loving from your iPhone hardware to work right. Basically, it seems it needs to “rebuild itself” on the software side. My first attempts were to turn the phone off and back on but this didn’t work. Turns out it needs a “hard reset”, not just a power off (one would think these were basically the same things, but nope). Here’s what I did and it fixed everything:

• Press and hold BOTH the Sleep/Wake button and the Home button
• You will see the shut off screen. KEEP HOLDING
• Wait for the Apple logo
• Release the buttons
• Wait a bit until it comes back up (mine took a couple minutes)

Bingo! It’s back to its old self with iOS4. Now I have my phone back and all is right in the world. Well… Except that I don’t have the iPhone 4 yet, but that’s another issue entirely. Hope this helps you out as well.

Edit: I guess there’s another way by doing a complete backup, reset to factory defaults and restore through iTunes, but who wants to do that? I guess if the previous method doesn’t work for you, give the old restore a try.

Have you experienced the same thing? How did you fix it? Please share!