Originally Posted by creepyncrawly
You need to provide more detailed information before anyone can help you. How were you attempting to root? I would guess from the result that you tried to flash a kernel with odin? If this is correct please provide details. If not correct, then please explain exactly what you did in detail.
For future reference, questions should be in the Q&A forum.
Thanks creepyncrawly for the quick reply! Okay, I had flashed a rooted stock rom to my Galaxy S2 (I don't remember the stock rom code) and then I don't know what got into me, but tried to flash another kernel from www.galaxys2root.com
which got me stuck in the Yellow triangle screen. But now I'm fine, I used portable adb and got into recovery mode and finally installed a stock unrooted rom (UCKH7). So I'm back to normal! Thanks again! For your help. Next time I'll read more and make sure I post the full details.
I really appreciate your help!