Today I rooted my I9300 with CF-Auto-Root and everything went fine.
Than I installed TeamWin Recovery 126.96.36.199 with GooManager, made backup and tried ti install CM11, but got error message that instalation was not succesfull.
I restored my backup, phone worked OK and than I installed CWM recovery with ROM Manager.
I restarted phone in recovery and made backup.
Making backup finished OK, then I restarted phone and got stuck on black screen with "Samsung Galaxy S3" text.
I wiped dalvik cache but phone is still stuck on that screen.
Then I tried to do factory reset but it restarts phone almost immediately.
I found one tutorial that sad to wipe data partition among other things and when I try to do it phone restarts, so I guess that there is problem with data partition.
I can get in Recovery and Download mode.
Sorry for my bad english.
Any help would be very appreciated.