I have s3 GT-I9305, android version 4.1.2, baseband version I9305XXBLL5. Australian model for Optus.
I successfully rooted and installed Philz_Touch_6.19.3 _ After that I could do Nandroid online backup and confirm it is rooted.
When I tried to flash custom ROM today - I found I can't boot in CWM/Philz recovery mode. Then I tried to different version of Philz/CWM and TWRP but none worked. It keeps booting in stock recovery mode- I get message as shown in attached image.
PS: I have USB diagnosis checked but haven't unlocked boot loader?