rescue disk with serial console

[Bjorn Helgaas <helgaas rsn hp com>]

Has anyone successfully created a rescue disk that uses only a serial
console?

It seems like this should be doable, but I haven't been successful yet.
I started with a 2.1.36 kernel (with serial console support), and put
it on a floppy along with LILO.  The LILO configuration specifies the
serial port and passes the serial info to the kernel.  This part works
fine; I get the LILO message and the kernel boot messages on the serial
port.

However, I also built an initrd containing only a linuxrc executable and
a few /dev files. linuxrc gets executed, but its printfs are garbled (as
though the baud rate is incorrect).  I added a /dev/cua0 and had linuxrc
explicitly open it, configure it, and print to it, but the output is
still garbled.  After linuxrc exits, the kernel prints still work just
fine.

Any ideas?  I see from the RedHat install init source that someone has
at least thought about this, because it understands a "serial" option,
but I sure can't get it to work.

Bjorn