I have a touchpad and an S3 personally, but my girlfriends S2 has been playing up for ages, and was looking to root/custom ROM, etc it.
I'm a little warey of it, as it's not my phone, etc (more happy to kill my own device). Main problem I am having is that it won't install anything due to lack of space (when it has over 100MB free on internal and GBs free on the USB part). I have seen a couple of solutions (*#9900# option 2, clear odex's and clear logs), which I will try.
My two questions are, I don't have root, or recovery or anything yet, is it OK to root the phone in this state, if the *#9900# option doesn't work, and 2 how do I go about flashing with Heimdall on Linux. I have searched high and low, and can't seem to find a 'good' way to the PhilZ kernels and flash with heimdall for the root part (once I've rooted it, I will just use CWM)