You know if you can get the full schematic you can probably do this non destructively. A lot of the YouTube videos use the snipping and pull up method that removes the osd and so on. You don't have to directly inject into those pins is the point. Just to the non ground side of a resistor in line with the pin. MarkOZLAD on the shmups forums has a general overview schematic in his signature in the rgb mod thread there.
The Future Is Now