Downgrade to 3.01
I can confirm that if you downgrade to 3.01 firmware Cinavia will not be in effect.. im trying this on a 40gb fat ps3 although i have a 120gb hard drive in it at the moment.
I was on 3.00 firmware than i upgraded to 3.41 so i could use multiman and play avchds.
i was first on 3.00 from messing around with downgrading noticed cinavia didnt work on this ps3 i thought it had to do with the broken bluray drive it hasda
when i was at 3.41 firmware cinavia came back and watching the other guys showed up half way through the movie and than every 4 seconds after that if i press circle and than x.
so convinced it was the firmware i downgraded back to 3.01( since 3.00 you cant jailbreak it.)
And now i watched the other guys all the way through along with the movie salt. Havent had any problems so far and i hope to stay here. Have fun