PSX PU-22 motherboard / Mayumi V4 modchip install - looking for help

Hello all! I'm new to the forums and have recently acquired some modchips with the Mayumi V4 code on them for my NTSC-U PSX (PU-22 motherboard). I followed these install instructions: https://dl.dropboxusercontent.com/u/28488139/Install Docs/Mayumi v4.docx

After install, I can still boot originals from my region (NTSC-U), but am unable to boot an NTSC-J original or any backups from any region. Here are pictures of my install (perhaps not the best soldering job, but I've seen worse): https://imgur.com/a/nNrfS

Am I missing something as far as the operation of the chip, or did I botch the install? Any ideas are very much appreciated.

 

Apologies for the post - I figured it out, the chip was wired incorrectly. 12C509 chips are wired:

1 - | | - 8
2 - | | - 7
3 - | | - 6
4 - | | - 5

I had mistakenly inverted the right side. Hope this helps future newbies!

 

FYI, all DIP chips have their pins numbered like that.