In article <200212241122.UAA01689@srapc342.sra.co.jp>
soda@sra.co.jp wrote:

> Changing CONSOLEIN/CONSOLEOUT is not recommended on ARC machines.
> 
> At least some ARC machines don't really support changing the
> CONSOLEIN/CONSOLEOUT variables. And there is no way to make the
> CONSOLEIN/CONSOLEOUT settings revert to the orignal state on
> such machines. (I don't know whether RiscServer 4200 supports it
> or not, though.)

Yes, even on machines that supports CONSOLEIN/CONSOLEOUT,
if you make a typo on changing the variables, ARC BIOS
just says "inappropriate device" (or something) and hangs.
There is NO fallback. 

> Izumi TSUTSUI once recovered a machine from scuh state by removing
> backup battery from the motherboard. But the way is not decent, and
> has some drawbacks. (e.g. the machine is now never be able to remember
> bios settings....)

ARC machines uses NVRAMs with built-in battery (DS1287 or compatible),
so you have to replace (or forcibly reset) NVRAMs.
You also have to search NVRAM address for MAC address to restore it..

> If one needs serial console with NetBSD/arc, I recommend to add a
> character `s' into to the "OSLOADOPTIONS" of the ARC BIOS....

"scsi(0)disk(0)rdisk()partition(1)\netbsd.ecoff OSLOADOPTIONS=s"
on "Run a program" prompt should work.

BTW, I'm working on support of Cirrus VGA at isa on R96/J96A machines.
This is based on Bob's patch and it is mostly working, but
more cleanup is needed before committing.
---
Izumi Tsutsui
tsutsui@ceres.dti.ne.jp