boot0sio working for anyone?

Ulrich Spoerlein uspoerlein at
Fri Feb 8 19:14:29 UTC 2008


I'm setting up some older FreeBSD releases on a headless machine and it
would be very helpful, if I could choose which disk/slice to boot from
via serial console.

I built all my boot blocks with BOOT_COMCONSOLE_SPEED=115200 and then
ran boot0cfg -Bb /boot/boot0sio (after installing them to /boot, of

However, upon boot nothing is printed on the vidconsole, nor the serial
one (tried tip(1) at the other end with -9600 and -115200 parameters). I
had to boot a 6.2 installation CD, chroot to my 8.0-CURRENT partition
and reinstall "normal" boot blocks to get at least the F1-F5 menu back
at the vidconsole (I do have a monitor hooked up for testing).

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.

     -b boot0
             Specify which `boot0' image to use.  The default is /boot/boot0
             which will use the video card as output, alternatively
             /boot/boot0sio can be used for output to the COM1 port.  (Be
             aware that nothing will be output to the COM1 port unless the
             modem signals DSR and CTS are active.)

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

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