"M-Chip from Taito Extermination B06_14.1G"
Chip decapped successfully, but it was a bit dirty despite initial cleaning attempts (above). Try again:
Better. Using crossed polarizers, ROM looks like this:
Getting there, but there's still enough debris to make readout difficult. One final more aggressive cleaning round:
And we have a good quality image prime for readout.
For reference, here's a sample closeup of conventional brightfield vs crossed polarizers imaging:
After imaging, a computer vision (CV) program analyzed the images to produce a ROM dump. However, instead of getting 0x800 bytes as expected, we got 0x900! After a closer look, we discovered the CV program had interpreted some address lines as data:
These were fixed and the ROM now looks reasonable. After a bit of work to understand ordering:
We now have the original ROM file.
However, additional checking needs to be done before it's ready to use (ex: dust induced single bit error).