Removing boot0

Paul Richards paul at
Sun Jan 14 16:21:24 GMT 2001

Ben H wrote:
> allo,
>  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 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.
> 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.


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