Yes, it is. To make it more easy for you, if you download and flash the firmware I have a link to in my previus post (which BTW comes as an auto flashing .exe, not a .bin), you will have a region free drive, no questions asked (that's what RPC1 means).
But the region lock you are experiencing could be a software problem. Maybe I am explaining the obvious, but I don't know how experienced you are and I'm trying to be as helpfull as I can.
So I'll quote Mad Dog, in case you don't know the following piece of information:
"An RPC1 firmware defeats the internal counters within the drive and removes region enforcement. This only is HALF of the equation. You need to use DVD Genie or similar software to control your player software. http://forum.rpc1.org/viewtopic.php?t=239"