How to restore iOS 5.1/5.1.1 backup to iOS 5.0.1

[youness]

For those downgrading from iOS 5.1 or iOS 5.1.1, I have successfully restored from my iOS 5.1.1 backup and kept all my settings after the downgrade.

I don't know if this is common knowledge, but just in case, here's how I did it:
(These instructions are for OS X)

1. Find your iOS backup file. (On a Mac, it's located at /Users/Library/Application Support/Mobile Sync/Backup

2. In the big jumble of files in there, find info.plist

3. Open info.plist with TextEdit

4. Locate <key>Product Version</key> <string>5.1.1</string>

5. Change "5.1.1" or "5.1" depending on which version you're downgrading from to 5.0.1.

6. Save the file.

7. Restore your iPhone/iPad with Redsn0w, ifaith...

8. Restore to that modified backup with iTunes.

9. Enjoy!

10. Profit.

[tylcr]

Follow these simple steps to restore iPhone from iTunes backup

You must backup using iTunes, not iCloud.

If you've already backed up your data using iTunes, skip to step 3.

1. If you did not Update to iOS 5.1.1 "
2. Backup your data using iTunes, not iCloud.
3. After that, locate your backup on your computer.
4. For Windows, it's at "C:/Documents and Settings/[USERNAME]/Application Data/Apple Computer/MobileSync/Backup". For Mac, it's "~/Library/Application Support/MobileSync/Backup"
5. Locate your latest backup and search for the info.plist file. Edit it with a text editor and look for this string: <key>Product Version</key>
6. Change 5.1 or 5.1.1 to 5.0.1 and save.
7. You can now restore to this backup on 5.0.1.