Remove GRUB?

[Fabian Keil]

Michael Dexter <dexter at ambidexter.com> 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:
> ><UNUSED>
> >The data for partition 4 is:
> ><UNUSED>
> >
> >note the flag 80 in the first entry.
> 
> The results appear similar:
> 
> localhost# fdisk ad0
> ******* Working on device /dev/ad0 *******
> parameters extracted from in-core disklabel are:
> cylinders=155061 heads=16 sectors/track=63 (1008 blks/cyl)
> 
> Figures below won't work with BIOS for partitions not in cyl 1
> parameters to be used for BIOS calculations are:
> cylinders=155061 heads=16 sectors/track=63 (1008 blks/cyl)
> 
> 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 81915372 (39997 Meg), flag 80 (active)
>          beg: cyl 0/ head 1/ sector 1;
>          end: cyl 1023/ head 254/ sector 63
> The data for partition 2 is:
> sysid 131 (0x83),(Linux native)
>      start 81915435, size 61432560 (29996 Meg), flag 0
>          beg: cyl 1023/ head 255/ sector 63;
>          end: cyl 1023/ head 254/ sector 63
> The data for partition 3 is:
> sysid 130 (0x82),(Linux swap or Solaris x86)
>      start 143347995, size 12948390 (6322 Meg), flag 0
>          beg: cyl 1023/ head 255/ sector 63;
>          end: cyl 1023/ head 254/ sector 63
> The data for partition 4 is:
> <UNUSED>
> localhost#
> 
> On a related note, once working, how does one configure the FreeBSD 
> loader to give the Linux partition as an option? It seems to have 
> happened "automagically" in the past.

Are you sure you are talking about the boot loader, not the boot manager?
I'd say boot0cfg is what you need.

Fabian
-- 
http://www.fabiankeil.de/
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