Every few months it's same story again - I need to update my iPhone IOS firmware to new release because there are some cool new features, some new apps just won't install without latest IOS or iPhone just became to crashy and unreliable that it needs a clean reinstall.
Sometimes update is done in mobile shop that some of my friends run and sometimes I do it myself. Because I do it so rarely I forget some of limitations set by Apple.
1. Upgrading IOS
- You can't upgrade to any other but the latest IOS released by Apple.
- this bit me two times as I saw that latest IOS had some thing that I didn't like to I tried to install to some other that latest version. This is just not possible.
2. Downgrading IOS
- You can downgrade only to IOS firmware that you had previously installed, jailbroke and saved shsh blobs from
So you can install only latest firmware released by Apple, your current one or previous ones that you have saved SHSH blobs from. Period.