Remove GRUB?

[Michael Dexter]

Hello,

I was experimenting with the GRUB bootloader and would now like to 
remove it. Something went wrong and I must now use a bootable CD that 
gives me an option to "boot to the first partition" and the system 
boots fine.

man bsdlabel gives:

Installing Bootstraps
      If the -B argument is specified, bootstrap code will be read from the
      file /boot/boot and written to the disk.

Assuming that this affects the mbr of the who drive, I tried:

localhost# bsdlabel -B /dev/ad0
localhost# bsdlabel: /dev/ad0: no valid label found

No problem, let's try the root partition:

bsdlabel -B /dev/da0s1a

No error, it blinked the hard drive activity light and appears to 
have done something but alas, it still reports a GRUB error 21 rather 
than given any sign of the FreeBSD loader.

Any pointers to the rescue/install procedures applicable to this?

Best regards,

Michael Dexter