How to Upgrade iPhone 4 to ios 6.1.2 instead of 6.1.3?

[hkwong]

1. How to I ugrade my iPhone 4 (ios 4.1) to ios 6.1.2 instead of 6.1.3? Some say download the ios 6.1.2 firmware first and after that open iTunes then press shift + restore and choose the firmware. Will that work for my current ios 4? Do I need to enter DFU mode first?
2. I have an another iPhone 4 which has been updated to ios 6.1.3 and I do not save any SSH using tinyumbrella or other tools for degrading. Can I restore the iPhone back to the factory firmware (ios 4) using iTunes and jailbreak it?
3. Can I transfer all the installed apps or cydia tweaks from a jailbroken iPhone to another jailbroken iPhone? Can i - Backup iPhone A first using itunes and after that connect iPhone B and restore by using the backup of iPhone A. It seems won't work. Lol

 

[natasftw]

1) You can't.

2) If you don't have SHSH, no you can't.

3) I'm going to assume your apps are legitimate, and not pirated. Login to the Apple store or Cydia and you can download your purchased apps for free. Apps aren't included in backups, but purchases are saved in each store.