Booting from usb hard disk

[Douglas Berry]

On Mon, 23 Mar 2009 05:36:15 CDT, Robert Noland wrote:
> So I have my i386 install on a usb hard disk, which I can only boot
> on one machine now.  The one machine that I can make work has a bios
> option that reads "BIOS ehci handoff".  This used to work with the
> old usb stack.  The machines that it doesn't work on, boot the
> kernel, but fail to mount root, giving me the forbidding mountroot>
> prompt, which is immediately followed by the message saying that da0
> is attached.  da0 is however not listed in the available boot
> devices list.  I tried playing around with the timeout in
> vfs_mount.c, but that didn't seem to have any impact.  It has been
> suggested that this may be a "geom" timeout, but I don't know
> anything about the boot system really.

I have been using tunefs(8) labeled partitions on my usb hard disk
under CURRENT. I changed the fstab entries to match the labels
(eg. assume mylabel is myroot, /dev/da0s1a becomes /dev/ufs/myroot)
It works well on most systems.  On some systems, I see the symptom
you show, but I am saved by the labels showing up just after the
mountroot prompt.  I am then able to type

	ufs:/dev/ufs/myroot

and resume the boot.  Maybe this helps you?

cheers,
doug