At last, I found a bit in EC RAM that is used to enable EC ACPI, so ACPI is working now. I copied the ASL code from vendor DSDT, and now battery, AC, and lid status change can be detected by OS now.https://review.coreboot.org/#/c/19072/
Having found the send speed setting, I got a bit interested in the file sending process itself. Tracing back a reference to "Sending....Press any key to stop. " text, I find sub_F013:F013 ; XXX prepare to send (flags and prompt) F013 sub_F013:...
Reading this Japanese article on a kit sold in Japan to build a Z80-MCB, I realized the presence of a possible bug seeing this two images: As you can see, there is a Z80-MCB without any Virtual Disk or RTC attached and in the resulting screenshot the...