Firstly. Think Calm Thoughts.
I agree, your phone should not break when an update goes bad, you *should* be able to roll back to the previous version. But you can’t, so…
I tried to update from from 2.1 to 2.21 on my 3G iPhone this morning and it refused to restart – claiming a very useful “error 13”… The Apple help was not useful for me.
To roll back to 2.2 I did the following – hopefully it works for you too, I did this from a different machine with an older iTunes – I am not sure if that is required.
1. Download the 2.2 firmware, Apple helpfully don’t link to prior versions of firmware on their site, but at the time of writing it is available on their Apple edgesuite link for iPhone 2.2 firmware, I guess this link might be dead for some future people, so search for this: “iPhone1,2_2.2_5G77_Restore.ipsw” you will find it someplace…
2. Then follow the simple instructions here, reproduced below just in case that page disappears:
Hold the SHIFT key while clicking the "Update" or "Restore" button in the iPhone tab in iTunes
Hold the option key while clicking the "Update" or "Restore" button in the iPhone tab in iTunes
Subsequently, a dialog box will come up which will allow you to select the firmware file to use for your update. At this point, simply browse to and select the firmware file that corresponds to the version you’d like to restore your iPhone with. (the 2.2 firmware you downloaded above)
Firmware files have an .ipsw extension and can be found at the following locations:
Documents and Settings\<User>\Application Data\Apple Computer\iTunes\iPhone Software Updates
~/Library/iTunes/iPhone Software Updates
Then after that step completes Restore from a backup that you have in iTunes. You should have a backup from just prior to the update you were trying to do.
Hope that helps.