The console can certainly be downgraded (I used to have this console as well until it broke). Your model consists of a 2k PS3 which is downgradable. If it was a 3k model or above then its a no. You do need a flasher however because they are many good fakes out there in the wild claiming to be able to downgrade your console. Which is false.
Please do not attempt a downgrade on your console using a firmware file. ALWAYS! Use a flasher.
If you do downgrade to 3.55, I recommend using Rebug 4.xX CFW