For all you who have booting psx games with a myth chip on v5-13 all you have to do is put the game in your system(duh) press the power button, hold triangle and circle right after that. You should go to the myth "infinity manager" and make sure your macrovision is off and boot is on auto. Then press start and wait till everything is saved. Then you will be prompted to hit reset. Hold circle to boot your psx games after that. hope this helps some people.

EDIT: o ya one more thing make sure your scex point is soldered correctly