It was advertised as getting very hot and wifi not working with an update of wifi working again after reflash to stock JB. On arrival the wifi would not turn on, I flashed the kernel without luck, it still would not turn on. I then decided to to give it a 8GB PIT and flash cyanfox. After all this it would freeze if I turned on wifi in cyanfox.
That said, this could be your problem, other people have found lots of symptoms depending where the acid goes, I have read reports of intermittent wifif, poor wifi and constant searching for wifi..
Most also report lots of heat, not sure if that's because of the short or the extra wifi activity, almost certainly high battery use but I can't confirm as I fixed it just a few hours after arrival..
Its easy to spot, take a look at the picks in the thread I linked to, just remove your main board (has to be removed as it's on underside) being very careful not to damage power or volume tabs, turn over the board and look for green residue next to the battery.
This is a great disassembly guide for anyone who has not done it before. https://www.youtube.com/watch?v=OCGBZKWWjfE
I was just not prepared to have this time bomb in my beloved S2.
Will disassemble again later... I'm pro now lol.... Thanks for Links.. Hopefully my issue is this......