How did you do this? I want to save messages and such that are on my phone at the moment just in case I'm forced to restore. Is it just a case of copying the significant files - such as sms.db - off the phone then copying them back on?
Say you want to restore your phone in iTunes. It will ask you if you want to back up. Let it do the backup and once it says its going to start restoring (the iPhone will probably turn off), pull the cable from the iPhone.
Locate the folder called iTunes_Control. Not sure what the root folder is - but its nested in a folder called Media. Delete that, reconnect the phone and iTunes will ask if you want to set up as a new phone or restore using a backup.
It will put your SMS/Email/Settings etc back on but won't tamper with the firmware.