Can My Galaxy S2 be reverted from Jelly Bean to Ice Cream Sandwich?

[Anonymous]

Hi Guys

I Have a Galaxy S2 which I've just accidentally upgraded to Jelly Bean (4.1.2), it's been prompting me for months to update it but I just disregarded it every 12 hours,  It did have Ice Cream Sandwich installed on it which ran perfectly (I think it was 4.1.1)

Since upgrading to Jelly Bean the phone has been very slow, my photo gallery app has changed to what looks like a Gingerbread version, the key tones have now been replaced by a bubble noise instead of the DTMF Tones (there no way to change that looking at it other than turn it off).

Overall the whole thing just runs slow, I haven't tried factory re-setting it as I have lots of photos which I'm just in the process of backing up on it.

The Phone is UK phone that has the O2 logo present when it boots up

Question is can the phone be taken back to Ice Cream Sandwich?

The Baseband number if it helps is : I9100PXXLS8

Kernal version 3.0.31-1246097

I'd like to take it back to ICS please if anyone can help

Cheers

Pete

[MI5 · Accepted solution]

Hi Pete
Yes, of course you can go back to ICS.
Your previous version would have been 4.03.
You need to use Odin for which I have written a guide here http://community.o2.co.uk/t5/Android-Devices-Samsung-HTC-Sony/HOW-TO-A-Guide-to-using-Odin/m-p/46346...
You will also need this firmware (register for free to download) http://www.sammobile.com/firmwares/3/?download=4914
Don't worry about warranty as it will not be effected at all by this process on your phone and no need to root either.
If you need anything else, just ask.....

[Anonymous]

Hi MI5 you are a pro!!!

I've followed all your guide and managed to get ICS back on the phone, just got to re-install all my apps now

Just a couple of questions to ask

Will I still get the pop-up to update to jellybean or will that now be gone? also if I wanted to "root" the device do you have a simple guide for that too as your other guide was fantastic!!

Cheers

Pete

[MI5]

Hi Pete
Glad you're sorted
You will need to go into "About Device" >software updates and turn off automatic updates, or else the phone will keep bugging you to update on a regular basis.
I'm not sure if I can talk about rooting here but send me a pm if you want to discuss it further