GRUB 0.92 on FreeBSD 5.x

Joshua Oreman oremanj at
Sun Jun 8 09:38:56 PDT 2003

On Sun, Jun 08, 2003 at 01:59:11PM +0100 or thereabouts, leon j. breedt seemed to write:
> hi,
> is it a new feature of 5.x disallowing direct writes to the device nodes
> /dev/ad*?
> getting weird behaviour trying to use the GRUB 0.92 port on all versions
> of 5.x i've used so far (currently on 5.1-RELEASE).
> the problem being that i can't see any disks in the 'grub' shell. the
> 'device' command works, and then a subsequent command like 'root' still
> fails with "No such disk".
> i've tracked down the problem to a call in the GRUB source where its
> trying to open(2) the device node /dev/ad0 with O_RDWR which fails with
> EPERM, which causes GRUB to delete the drive from its device map without
> any warning, just silent failure.
> i am running the 'grub' executable as root though.  
> when i patch that section of the source file (asmstub.c, function
> get_diskinfo()) to accept EPERM and only open in read-only mode,
> suddenly i can see my drives. but obviously anything wanting to modify
> the drive, like 'setup', fails.
> is my only recourse to install GRUB from floppy when using it from
> FreeBSD?

I think so. GEOM makes it impossible to write to disks that are currently
"in use". Best bet is to boot from a floppy.

-- Josh

> please cc me on replies, i'm not subscribed to -questions.
> thanks
> leon
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