Picked up a used ECU, the seller didn't know if it was unlimited or limited so when it came in I opened it up to see if it had any markings on the labels, well someone managed to pull the labels off both rom chips exposing the photosensitive part of the chip.


How screwed am I?

 

I may be alright, was able to dig this up:

Erasing an EPROM and the window

Usually an EPROM, once it has been programmed, will have a cover or sticker placed over the window. You cannot erase an EPROM or change its contents by removing this cover and exposing it to normal room light. Even in direct sunlight it would take two weeks of constant exposure to alter the chip. You cannot erase an EPROM with a black light or tanning bed, it is best to use an eraser manufactured to erase EPROMs and other programmable devices.