Removing boot0

Ben ben at
Sun Jan 14 23:48:35 GMT 2001

On Sun, Jan 14, 2001 at 04:21:24PM +0000, Paul Richards wrote:

> >  anyone know a cunning way of removing the boot0 boot loader from a disk?
> Depends really on what you're trying to achieve. I can remove the boot
> loader without too much effort, something along the lines of 
> dd if=/dev/zero of=/dev/da0 count=63 bs=512
> (don't try that as it might not be quite right and trash your disk but
> something like that will do it).
> That's probably not what you want though.

i just want to remove it so it boots staright into LILO not FBSD boot then

> > i cant use fdisk /mbr as it's a SCSI disk and isnt seen.
> That's a problem with your DOS disk, you need to make sure the SCSI
> drivers are installed from config.sys and the the SCSI disks will appear
> as normal.

dunno, only really have a book disk..

> > i can use /stand/sysinstall as it's now got linux on it (dont ask).
> > 
> > i tried booting off the CD, using configure menu, fdisk, selecting standard
> > boot loader and nowt really happened?
> Yeah, I've noticed that myself it seems to just be the standard boot0
> that FreeBSD uses whereas you tend to expect it to be more like DOS's
> boot blocks that doesn't have the OS selection step.
> You can do something else with dd though to put a DOS mbr back on the
> disk. Get a standard DOS boot floppy and do
> dd if=/dev/fd0 of=/tmp/mbr bs=512 count=63
> then write that image to the hard disk
> dd if=/tmp/mbr of=/dev/da0 bs=512 count=63
> but again, that's off the top of my head, someone else should check the
> figures and confirm whether they're right or not but that's the concept.

cheers, erm, count=63 doesnt that mean 63 512 blocks?

surely it's just one?

Ben Hughes, <ben <at> necrofaeries <dot> net>
 "Whenever anyone says, 'theoretically', they really mean, 'not really'."
                -- Dave Parnas

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