In an effort to get past the "Rebooting to System ACE Configuration
Address 6..." message, I have selected "support for early boot texts
over serial port" in kernel debugging.
This will not work. Unfortunately linux here shows its roots as PS OS,
there is a vast amount of hardcoded NS8250/NS16550 knowledge in there.
I'd started modularizing this so we could use a UART lite but the more I
dug the lower my motivation. This is really ugly code in an area that
is of virtually no interest. For now get rid of support for early boot
texts over serial port" and use your JTAG to read the buffers if you
panic before the console is up and running.
UartLite early boot text support is fairly trivial. It is also
fairly standalone.