Being an owner of the Samsung Galaxy S2 I've eagerly been waiting for my bite of ICS loveliness which never seemed to be coming. Turns out that I have even longer to wait seeing as I was one of those splendid people that bought an unbranded sim-free version online rather than from a carrier. A spokesperson announced that us folks would be last in the queue so I decided to move to ICS with by moving to the nightly builds of Cyanogen mod 9.
Step 1. Due to the locked boot loader I followed the directions here at CNet UK (Link via Andy Gibson) to root the phone. Note that: -
- I had to follow the link off the XDA forum to the older kernels for my phone.
- I put the secure kernel back on.
On this step I found that for some reason I was getting errors after attempting to boot in recovery mode and so was unable to apply the ROM. I have to apply a version of the clockwork recovery that was 188.8.131.52 which was linked off of XDA developers. After applying this I was able to flash on Cyanogen mod via the SD card.
Job done, I had a Galaxy S2 running Cyanogen mod 9.
The next day I decided that I did not like the yellow triangle on my boot screen and thought I would be okay to flash on the original secure kernel. Big mistake. I now had a phone that would not boot. Fortunately I could boot to download mode (via key press) and so I reapplied that clockwork mod kernel and then had to reinstall Cyanogen mod and the Google apps. At this point I decided I was now okay with the yellow triangle on start up but for some reason now when I went in to recovery mode I was now in the version of recovery that came with ROM manager.
So there you go... not as easy as it should be but I got there in the end. To be clear, I'm not recommending this as a specific method that may work with you, I just thought I'd share my experience with the whole process.
Good luck, I'll see you on ICS.