I have an iPod Touch 3G with 3.1.3 firmware that I recently purchased which was crashing. So I decided to return it to the store and get another one.
I had updated from 3.1.2 to 3.1.3 before iOS 4 came out.
So I tried to use the Restore button in iTunes to reset the iPod.
But I was getting the error "the ipod could not be restored. this device isn't eligible for the requested build." What?
So I did some web research and found that you could select a firmware on your computer by option clicking the Restore button in iTunes.
I tried that. No good. I downloaded from Apple the 3.1.1 firmware.
I tried three different versions, but all gave the same error and would not restore.
I started getting the feeling that Apple was forcing everyone to use iOS 4.
I did want to use it, but I did not want to be forced to install it at that moment.
So to restore the iPod, I had to download iOS 4, but I couldn't until I downloaded iTunes 9.2. So again, I was forced to update just to reset the iPod.
I tried the iOS 4 restore and it worked with no error. WTF!
By Apple's totalitarian decree, I downloaded iTunes 9.2 and iOS 4 and reset the iPod. I did backup the iPod Touch before doing the reset.
When I restored the backup to the new iPod Touch, all was not well. Lots of lost data and other problems, but that is another story.
If I was given the choice to restore to 3.1.3 and later update to iOS 4, it would have worked better. What a hassle!