My phone is a Samsung Galaxy S2, purchased in Singapore. The OS is Android 4.0.3. I wanted to root it, and followed the method specified in this xdadevelopers post.
My kernel is
*LPB* (I dont remember the whole thing, and that post says only these 3 letters are relevant anyway).
I tried to follow the instructions and flash both the LPB kernels suggested in that post, but in both cases, while booting, my device shows the Samsung screen with the yellow triangle and then immediately switches off.
I am still able to go to download mode.