Resetting bootloader on a CF

Michael Sierchio kudzu at
Thu Sep 1 15:21:15 UTC 2011

It occurs to me that there may be a couple of other wrinkles.  There
are kernel boot parameters that tell which kind of console to use, and
there are switches you can twiddle in /boot/loader.conf, notably

#console="vidconsole"           # A comma separated list of console(s)

           console   (``vidconsole'') ``comconsole'' selects serial console,
                     ``vidconsole'' selects the video console, and
                     ``nullconsole'' selects a mute console (useful for sys-
                     tems with neither a video console nor a serial port).

Also make sure that /etc/ttys launches a getty process for whatever
console you are using.   I.e., make sure it doesn't look like this one
(mine) - make sure that at least ttyv0 is on.

console none                            unknown off secure
ttyv0   "/usr/libexec/getty Pc"         cons25  off secure
# Virtual terminals
ttyv1   "/usr/libexec/getty Pc"         cons25  off secure
ttyv2   "/usr/libexec/getty Pc"         cons25  off secure
ttyv3   "/usr/libexec/getty Pc"         cons25  off secure
ttyv4   "/usr/libexec/getty Pc"         cons25  off secure
ttyv5   "/usr/libexec/getty Pc"         cons25  off secure
ttyv6   "/usr/libexec/getty Pc"         cons25  off secure
ttyv7   "/usr/libexec/getty Pc"         cons25  off secure
ttyv8   "/usr/local/bin/xdm -nodaemon"  xterm   off secure
# Serial terminals
# The 'dialup' keyword identifies dialin lines to login, fingerd etc.
ttyd0   "/usr/libexec/getty std.9600"   dialup  on  secure

On Thu, Sep 1, 2011 at 12:59 AM, Polytropon <freebsd at> wrote:
> On Wed, 31 Aug 2011 23:47:22 +0200, bsd wrote:
>> Part of the solution seems to be :
>> 1. Mount the CF on a FBSD
>> 2. Initialize the bootloader with :
>> # fdisk -B /dev/<disk>
> Erm... You should _not_ mount (as in /sbin/mount) the CF
> in order to change MBR data; mounting should be restricted
> to its humano-mechanical part. :-)
>> 3. This is where I need you help…
>> How can I re-install a boot loader ?
>> Should I use the command :
>> # fdisk -B -b /boot/boot0 device
>> Any other suggestion, guidance will be welcome.
> You can use sysinstall for that: Configure, select the CF card
> to work on, don't chance anything with the slices in the fdisk
> editor, just make sure the slice is marked active, and in the
> next step, select the default MBR to be written.
> The command line way should be:
>        # fdisk -BI /dev/da0
>        # fdisk -B -b /boot/mbr /dev/da0
> (Assumption: /dev/da0 is the CF card.)
> Note that the first step will re-initialize the card. If you don't
> want to build it from scratch, i. e. _only_ modify the MBR, the
> second command should do it.
> See "man fdisk" for details on the fdisk commands.
> --
> Polytropon
> Magdeburg, Germany
> Happy FreeBSD user since 4.0
> Andra moi ennepe, Mousa, ...
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