My 3G (w/ the 4 GM) routinely freezes to the point where it just stops responding to input. I'll probably attempt to downgrade it to 3 soon. Which, I honestly don't mind. I mean, I would rather Apple not even support the 3G with iOS 4 rather than have to deal with this user experience. It's not like it can even deal with background tasks anyway...
Same problem here; iPod frequently doesn't respond to headphone controls, and apps slow to a crawl and become unusable ( >1 minute to respond to clicks).
Do you test/debug apps on your phone? Is it possible that this is triggered by using debugging tools? It seems like everyone else is not seeing what we're seeing.
Interesting, my 3G had the exact same problems as you (just froze and didn't respond to anything for like minutes at a time) with OS 3. But the problems have gotten a lot less frequent with OS 4 for me.
I read somewhere that upgrading a 3G from OS 2.x to one of the OS 3.0 betas and then to OS 3.0 final, without doing a full reset somewhere in between would cause this problem. OS 3.0 was sluggish as hell for me until OS 4.0 beta came out and I did a full reset. I'd get random pauses and freezes just like others here are reporting. After the full reset, the 3G was running smoothly again. I just upgraded to 4.0 final and it is smooth too.
A full reset kind of sucks. We're not talking a restore here. Just start from scratch. With the exception of one or two apps though, my data was in the cloud so it was largely painless to get everything back in sync.
Then why do people pay more money for phones that haven't been upgraded? I figured it was because you can't go backwards and the newest versions can't be unlocked.
When you try to install a firmware on your device (whether it's iOS 4.0 or iPhone OS 2.0), Apple signs the firmware using some combination of a unique identifier and other things to make sure you should be able to install it. When they release a new firmware, they typically stop signing the old firmware days or weeks afterwards, meaning you can't downgrade to it anymore. Also, there are checks on the device so even if you do manage to install it, you'll need to run certain commands to get it to boot up the first time.
The newer 3GS is harder to downgrade and you also can't downgrade the baseband (modem firmware) version, but you should be able to downgrade the actual operating system without any trouble.
Got it working. I followed the instructions and got stuck with error 1015.
I had to do two things.
1. Switch of your iPhone and put it in DFU mode with following instructions
- Click the Home + Power On button for 10 seconds exactly
- Release the power button and continue to click on Home
