depends on wat wwe 06 game u have, umd or iso. either way, its not possible to play either on a 1.5, however, if u upgrade to 2.0 and install pspsetx on ur psp and make ur psp think its 2.5, then its possible to play the umd with downgrading the psp to 1.5 later.
I have the original Smackdown vs raw 2006 UMD and also wanted to know how to get it working with my 1.50 firmware version PSP. Is there a way to play PSP games that require firmware above version 1.50 directly off the UMD game disk without storing it on to the memory stick as an ISO or files?
if i remember 3d said he maid a raw dump of the smackdown umd, then replaced the prxs with swbfII and rebuilt it, and didn't take anything out.