Rooting an old Samsung Galaxy SII

esuhl

Right. So I can use Odin to apply a patch that roots the phone, and to copy a custom recovery program and ROM image to it?

And... the custom recovery program replaces the bootloader with one that can then install the custom ROM?

Is that right? And if I re-flash with the original Samsung ROM, will that restore the original bootloader as well as the OS?

arriva

I have been tampering with my Galaxy SII since I upgraded to a new phone a couple of years ago. Among the various ROMs I have installed (including the Samsung stock ROM which in 2016 is a little out of date IMO) I found Cyanogenmod 13 to be the best I ever tried.
I followed this video which makes things very easy, the instructions are spot on and the procedure is quite straightforward. You can probably do it without a computer.

https://www.youtube.com/watch?v=-wDsvNmKlxE

the two great advantages are:
1) it re-partitions your internal memory allocating more space to the system+apps (so no more "not enough space on the device" messages while trying to install extra apps).
2) it installs Marshmallow 6.0.1 to your Galaxy SII

Surprisingly, after the upgrade to Marshmallow the phone doesn't lag and it seems to be very stable (I have been using it as a second phone for 3 weeks and so afr it has been outstanding). Wifi, GPS, bluetooth, 3G data, OTG working all fine.
I had X-posed on a previous Cyanogenmod edition (I think it was version 11 or 10) on the same phone and it worked flawlessly but didn't get around installing it on Cyanogenmod 13 as the system comes with so many privacy tweaks that it seems unecessary at the moment. I read the framework is compatible with this system so you can always install it.

..and, yes: the Cyanogenmod 13 has the "give root privileges" switch built-in, it's buried in the Advance Settings so no need for extra flashing.

the built I installed was this one: "cm-13.0-20161012-NIGHTLY-i9100"

esuhl

Thanks -- that's really helpful. I'd been wondering about upgrading the kernel to a later version.

I'm just about to bite the bullet and give it a go, but I can't find a copy of the original stock firmware on the Samsung site. There are other places to download it, but I can't be sure whether they are the genuine originals. :-/

Does anyone know whether the firmware is still available from Samsung? Or if not, the safest place to download a copy?

It's for the Samsung Galaxy SII:

Model number:
GT-I9100

Android version:
4.1.2

Baseband version:
I9100BULS3

Kernel version:
3.0.21-1484249
dpi@DELL177#3
SMP PREEMPT Tue Dec 3 20:24:29
KST 2013

Build number:
JSO54K.I9100XWMS2

[Deleted User]

If no one has a link, message me later, I thin i have a back up copy and a hard drive at home, I can upload it to Google Drive if you like.

arriva

there are a lot of sources of stock firmware for Samsung i9100 out there but you could extract yours from your own Galaxy using this procedure (I didn't try it so I cannot vouch for it):

http://forum.xda-developers.com/showthread.php?t=1777579

I think if you restore the phone to factory then what you extract should be the "clean" stock ROM your phone came with.

A couple of points to note though: after you tried another "flavour" for your Galaxy S2 you probably don't want to revert to the old boring stock ROM I bet you will want to try another mod, they are much more fun...
The second point is that you should do some research to check whether the re-partitioning of the internal memory prevents the original stock ROM to be restored. I don't see why not as a larger patition is an improvement but you never know.

forgotmyname

Get one of the one click options off xda website. So simple.

Not quite one click but simply attach phone to PC in recovery mode/safe mode etc, and run ODIN, upload a file to the phone and restart the phone, its that easy.

JJ_Egan

i9100

http://www.sammobile.com/firmwares/database/GT-I9100/

Depending upon what phone firmware you have . probably VOD judged by your modem/baseband .

Antispam

I used this on my old s3

https://kingroot.net/

You can also un root it as I did last week when I sold it on

esuhl

Well, I managed to install CWM recovery, then Cyanogenmod 12 using the guide here:
https://wiki.cyanogenmod.org/w/Install_CM_for_i9100

And then I thought I'd try to follow the instructions in the video suggested in post 13 to repartition the device and then reinstall Cyanogenmod.
https://www.youtube.com/watch?v=-wDsvNmKlxE
http://galaxys2root.com/galaxy-s2-roms/how-to-install-cm13android-6-0-1-marshmallow-rom-on-galaxy-s2-repartition/

But I'm literally stuck at the first step -- installing IsoRec_TWRP!

I was surprised to see that installing CM12 also replaced the recovery with Cyanogenmod recovery. I tried to install IsoRec_TWRP via CWM recovery, but it didn't do anything.

The video guide says you need to start with either CMW or TWRP, so I reinstalled CWM (by following the first part of the Cyanogenmod installation guide), and tried again to reinstall IsoRec_TWRP.

From the terminal output on-screen, the installation appeared to be successful, but when I rebooted to recovery, CWM loads again instead of IsoRec_TWRP...

I'm baffled (again!)... Any ideas...?

DoaM

Antispam wrote: »

I used this on my old s3

https://kingroot.net/

You can also un root it as I did last week when I sold it on

I used that on my Nexus 4 too, when the USB cable stopped working and something had gone wrong and I needed to re-root. Avast or Malwarebytes (I can't remember which) on my PC mind didn't like the APK though, but I can't remember why.