Just tried it with my PSP-2K, 5.00M33-6. Game decryptor doesn't work, both v1 and v2 fail to load the eboot.bin and refuses to do anything after that. The game itself needs 5.55 fw, I'm going to load it up and see if it runs anyway.
Waiting for my Macross UF UMD to arrive from yesasia...might...