How to upgrde iPhone without upgrading to the latest firmware

[texastravis]

Cant find anything on this because im not really downgrading. I am trying to upgrade my iPhone 3g iOS from 3.1 to 4.1 (not the latest 4.3 stuff). How do I do this? I have gone online and downloaded the 4.1 iOS for iPhone 3G but not sure how to install it?

I thought holding shift then clicking update and selecting the downloaded file would do it but it did not. It didnt find a compatable file to click from my downloaded 4.1

Any ideas? Thanks

[j3st3r]

you will need to have shsh's for 4.1 if you are updating to official firmware, also make sure you are using either chrome or firefox to download the firmware (it should end in .ipsw)

[texastravis]

What do you mean by SHSH. Do you mean I just need to back up my current SHSH files using Umbrella?

Sorry, dont know much about this....just using the google

[iYeow]

Shsh blob is needed for verification of any firmware restore of 4.xx. When apple stops signing a firmware , it also stops the shsh blob for that particular iphone firmware. If you have save the blob with cydia or downloaded onto your computer. In order to restore to the firmware when apple has stop signing, you either need to point your hosts file towards cydia server or start TSS Server within your computer using Tiny Umbrella.
Example : let say you want to restore to 4.1 firmware. You need to run tiny umbrella, plug iphone in and click save shsh. All available shsh blobs from Cydia will be downloaded onto your computer. If you do see 4.1 shsh blob in TU, then you click start Tss Server and let it run throughout your restore to 4.1 firmware thru itunes.

[i.Annie]

Try iFaith from ih8sn0w.com. I don't know much about it yet or how it works, but I believe it allows you to get SHSHs for the fw on your device and creates a presigned firmware to restore to. In your case it would be 4.1.

It's new so...I have no idea how it really works yet.

[texastravis]

Hmm....well I downloaded with firefox and that worked. I restored the phone with the 4.1 and now it seems to run just fine....

Will I experience any problems for not using SHSH?

[i.Annie]

What did you download?

Well anyhow if you restored successfully to 4.1 there isn't anything to worry about.