Well in the process of upgrading to 4.2 I had to do the following:
Painfully wait through 8 hours of backing up the iPad
During the upgrade process it looked like the process was hung up and I pulled and recoonectednthe USB cable. By doing this I had to restore the iPad. No worries right? I just had the entire iPad backed up.
Well, after restoring and upgrading I found that there were many apps that were missing. I'm surprised that the restore didn't bring the iPad back to where it was before the upgrade. I estimating that about half of the apps are missing.
Has anyone else had this problem?
When you restore your iPad, only the apps that initially came with ipad will be there. The iPad is restored to it's orig state, when purchased. You have to reinstall your personal apps again, thru iTunes. At no charge, of course.
Most of the lock ups are due to slow connection and over due back up. My download speed averages about 24 to 26 thus my upgrade took a blazing speed and finished inside 25 minutes. I back up daily including the purchased apps.
You can not get it back unless you back up.
Plug in to iTunes, right click on your device in the left column and click restore backup then you should be able to choose from your backup files and get your setup back.
Mine took 3hrs 20mins and mine 32g is almost full.