If it’s physically impossible to write to a ROM (read-only memory) cartridge, how do manufacturers do it?

Question

Is somehow locked physically during production, or through software?

In: 210

Answer 1

Mask ROM as the name implies uses lithography to “print” the wire connections onto the memory region of the chip, since data’s are all 1s and zeros or connected, not connected.

Once the data has been printed on, the silicon wafer goes into the package, the black thing with metal legs, and no further modifications can be made.

Otherwise a cartridge could use EEPROM, a form of NOR flash, which can be written electronically but the “writing function” is just disabled once the chip goes in the cartridge.