Remove GRUB?

Glenn Dawson glenn at
Tue Jul 19 10:34:46 GMT 2005

At 03:25 AM 7/19/2005, Michael Dexter wrote:

>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?

Did you use fdisk to check and see if the first slice is marked as active? 
Here's a sample from one of my systems:

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
     start 63, size 10474317 (5114 Meg), flag 80 (active)
         beg: cyl 0/ head 1/ sector 1;
         end: cyl 651/ head 254/ sector 63
The data for partition 2 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
     start 10474380, size 10458315 (5106 Meg), flag 0
         beg: cyl 652/ head 0/ sector 1;
         end: cyl 1023/ head 254/ sector 63
The data for partition 3 is:
The data for partition 4 is:

note the flag 80 in the first entry.


>Best regards,
>Michael Dexter
>freebsd-questions at mailing list
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