boot0sio working for anyone?

Ulrich Spoerlein uspoerlein at
Sat Feb 9 10:28:52 UTC 2008

On Fri, 08.02.2008 at 13:12:43 -0700, Scott Long wrote:
> Bruce M. Simpson wrote:
> > Ulrich Spoerlein wrote:
> >> So, is boot0sio supposed to just work with a cheap USB->RS232 dongle at
> >> the other end? I don't know how this paragraph from boot0cfg(8) is
> >> affecting me.
> >>   
> > boot0sio is wholly dependent upon BIOS support for addressing the on-board 
> > COM1 port. It is not intended (read: very unlikely) to work with USB 
> > dongles.
> > 
> > If your BIOS does not support the call that it uses, then the symptoms will 
> > be similar to what you've seen. Unfortunately there is just not enough 
> > space in the MBR to implement any workarounds for this.
> > 
> Yeah, unless the BIOS provides traditional SIO emulation via USB (similar 
> idea to providing tradition AT keyboard emulation via USB)
> then boot0sio won't work.  It's not very feasible to put a USB
> stack into the early boot loader anyways.  It's somewhat possible
> (at least, using a chained boot loader), but not very feasible.

Erm, you guys got that one wrong. boot0sio is running on a machine
without USB! It is the *other end* of the line (my laptop) where
I'm using tip(1) on /dev/cuaU0. And I'm not sure if this provides the
necessary signals to boot0sio to start working.

So, to recap the question: Is boot0sio working with 9600 or 115200 baud
for anyone on 8-CURRENT (and built with gcc 4.x)?

Ulrich Spoerlein
It is better to remain silent and be thought a fool,
than to speak, and remove all doubt.

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