Can you do a high-res image of the remaining portion of the tmc0271 rom? about 80% of it is still readable, and could be useful to compare against the patent firmware (which i suspect matches the 'bug fixed' 1979 one, hence we need this older rom on the chip).
Also, can you image the 4 rom areas of the tmc0281? It is an older '0280 A / 281' chip, while the tms5100 on siliconpr0n is '0280 B / 281 A' which is newer. https://dl.dropboxusercontent.com/u/7909...die%20small.png shows the rom areas on a tms5200, but the 5100/0281 has the rom areas in question in (nearly) the same places on the die. (ignore the copyright area, its in the upper right on the 5100/0281 and i can see it in your low res image just fine)