~Let's make 30-year-old pocket organiser Casio Business Navigator BN-20 run some new software, part 4~

Recap of the previous episodes: our friend gave us a pocket organiser. As it happens, the organiser is based on Intel 8086-compatible core. It is related to Casio Pocket Viewer series, but unlike the PV, it doesn't have a way to "side-load" the applications.

So far we've dumped the ROM and tried to use it with Casio PV SDK. PV is compatible enough to kick-start the boot process, but the simulated OS crashes before it can even draw anything.

One interesting lead I decided to follow was the discrepancy between the CPU models in BN-20 and PV series: BN-20 runs on NC3020, and PV runs on NC3022. The documentation for Casio PV SDK mentions that a publicly-available simulator for NC3020 was a thing, too.

Can we find it? Can we run it? Yes we can!
🧵