iphone
My friend has an iPhone 4. Yesterday it got disabled after several failed passcode attempts. When you press the turn on/off switch or the home screen button, the following message appears:
iPhone disabled. Connect to iTunes.
The problem is that it was synced with a computer she doesn't own anymore. And she doesn't want to lose any of her data. I wonder if it could be recovered without any data loss.
Which iPhone OS and model do you have? The newer ones encrypt the data and the erase deletes the key. The chances of DIY recovery are slim. If you pull it off, you probably can get hired for iPhone forensics and make some serious salary doing that professionally.
Older devices are more amenable to typical recovery efforts. Either way you will need a forensic tool like PhoneView to access the filesystem. Once mounted you could try something like Data Rescue. Neither tool was designed for this, so you should try the free versions first before spending money on them.
The professional data recovery houses will likely charge an arm and a leg to get your data back - but at least you can get a quote if you really need them back at all cost.
Be sure to double check your camera roll isn't backed up to iTunes or on Time Machine. It would be far simpler to restore the device to an old backup and get the photos off intact. You would lose any photos taken after the backup time, though.
If you have enabled data security (iOS 4.3 and iPhone 4 are one combination that enables this security), you're likely deep in the hurt locker. See iOS 4: Understanding data protection to tell if you enabled data protection. In a nutshell, that means the filesystem was encrypted and the erase destroyed the key to the encrypted files. You will need industrial grade forensics to get things back if the phone was powered off immediately after the erase. Using it after the erase will rapidly overwrite the scrambled data irreversably.
You can use the Cleanup: remove all contacts app from the appstore to do this. The app costs $0.99
If you want a Mac only solution, you can backup the contacts in your mac's Address Book, connect your phone to your mac and set it to sync only your address book in iTunes. Once it's done syncing (it should now be a clean slate), you can change the sync settings to whatever you wish and then restore your existing contacts from the backup.
Best Answer
The only way if you don't have a backup (on pc/mac or iCloud) is to recover data with a third-party software before you attempt to restore with iTunes.
This one is well reviewed (but not cheap).