Okay, then. The system would boot, but it would crash shortly afterward because the RTC emulation wasn’t ready yet.

A small patch, and the BIOS ignores the RTC. This allows the system to boot, but without the settings saved in the RP5C01’s memory, that red logo appears and the text is the same color as the rest of the screen. There is nice discussion about it here.

It’s time to emulate the RTC. On the first try, the system actually boots (with the red logo again) and the screen goes completely white. After a reboot, same thing. Another reboot, black screen. Maybe there’s a problem with the code that emulates the RTC.

By simulating a few keys (I DON’T have a keyboard… :-/), the screen returns to normal! I think before I dig into the RTC code, I’m going to build a keyboard.