@dangoodin they're just EEPROMs most of the time, since they don't need to get their own custom ASICs designed and fabricated and can just buy the bare dies or chipscale packages. sometimes they also include some sort of passive "security" check like adding a specific resistance across pins which the printer can detect. some use EEPROMs that offer write or read protection on blocks, where an unlock command must be sent to unlock it. trivial to defeat in practice.

@dangoodin those EEPROMs will contain some magic data that the printer needs to see in order to believe it's a legit ink cartridge. it also tracks the number of printed pages so the cartridge can claim to be empty after a while (they don't detect ink level at all).

I can 99.999% guarantee that even with the most optimal trivial exploit for the printer firmware's parsing of the cartridge data, you cannot weaponise it in any useful way. Why? Because the whole thing is like 32 bytes.