Installing stock JellyBean in Galaxy S2 [Argentina] The system that came with my Galaxy S2 is heavily bloated. I want to install a bare, stock Jelly Bean ROM. I've searched and searched, but keep running into walls.

System version

I don't know how to get the version string, or if I do, I can't find appropriate ROMs. Nothing I can come up with reading the system info comes up in the lists.

Model: GT-I9100
Baseband version: I9100UHMS1
Kernel version: 3.0.31-914166 se.infra@SEP-122 #3 SMP PREEMPT (date) KST 2013
PDA: I9100UHMS8
CSC I9100PSNMS4


Where can I get the correct stock Jelly Bean ROM?

Download mode

When I reboot the phone holding vol+home+power, I don't see the screen everyone says I should see. Instead, I see a menu, in which the most appropriate option seems to be apply update from adb, but ODIN doesn't see my phone at this point (it does show up when it's normally functioning).

Why does ODIN see the phone when it's ON, but fails to see it when it's in dowload mode?

To root or not to root

Do I have to root the phone before attempting to install a ROM? The rooting process, according to the guides I've seen, involves installing a ROM too. This takes me back to square zero and the problems above.

Please help!
You can get an almost stock Jellybean experience using SuperNexus - I9100. It is based off AOSP and only has "improvements and optimizations", but states it is still very near to stock. Another option, while differentiating itself from AOSP, is CyanogenMod. This is based on AOSP, but includes a LOT of extra features and improvements of AOSP, while keeping the bloat to a minimum.

As for instructions on getting it ready for a custom ROM, the instructions on the CyanogenMod wiki tend to be fairly accurate and may give you the needed information to get you started. Install CM for i9100 If you don't want CyanogenMod on your phone, replace step #2 in the last section with whatever ROM you want to try (like the one above). Make sure you get the right gapps (basic Google apps including the Play Store) unless your ROM includes it (most don't).