Re: GRUB2 chainloading GPT NetBSD partition

[beaker%sdf.org@localhost (beaker)]

mlelstv%serpens.de@localhost (Michael van Elst) wrote:

> beaker%sdf.org@localhost (beaker) writes:
>
> >mlelstv%serpens.de@localhost (Michael van Elst) wrote:
> >> In your case however, you provide your own MBR (with grub)
> >> and 'gpt biosboot' would just overwrite grub with our boot
> >> program.
>
> >Thanks for that explaination.  It does seem like I could do
> >a targeted storage with
>
> >  # gpt biosboot -A -i 3  # gpt3 == FFS netbsd partition
>
>
> This will overwrite grub and store our special GPT bootloader
> for BIOS on disk block 0. It will also mark GPT partition 3
> as 'active'.
>
>
> >which is how I managed to wipe out GRUB the first time.  Also
> >is the default bootcode (XXX) correct or should another boot
> >code be used via '-c' for this non-UEFI + gpt scheme? 
>
> The default bootcode for this is gptmbr.bin and we don't
> provide an alternative that you could select.
>
> In any case, you still need to install a PBR (like bootxx_ffsv2)
> to partition 3.
>

Okay, after doing a full backup I tried the following:

# determine which wedge to install primary bootstrap to:
$ sudo dkctl wd0 listwedges
/dev/rwd0: 6 wedges:
dk5: e8b85d79-899f-4cd6-964e-af3db098e992, 2048 blocks at 2048, type:
dk0: Boot, 1046528 blocks at 4096, type: msdos
dk1: Debian, 268435456 blocks at 1050624, type: ext2fs
dk2: NetBSD, 125829120 blocks at 269486080, type: msdos  # <<<
dk3: Commons, 83886080 blocks at 395315200, type: ext2fs
dk4: Swap, 9195520 blocks at 479201280, type: swap


# install FFSv2 primary bootstrap to /dev/rdk2:
$ sudo installboot -fv /dev/rdk2 /usr/mdec/bootxx_ffsv2
File system:         /dev/rdk2
Primary bootstrap:   /usr/mdec/bootxx_ffsv2
Boot options:        timeout 5, flags 0, speed 9600, ioaddr 0, console pc


# reboot and attempt GRUB 'chainloader (hd0,gpt3)+1':
=> ERROR NO SLICE


I then tried uninstall the primary bootstrap but it seems that isn't
supported on i386:

--
$ sudo installboot -c -fv /dev/rdk2
File system:         /dev/rdk2
Primary bootstrap:   (to be cleared)
installboot: i386: bootstrap removal is not supported
installboot: Clear bootstrap operation failed
--

Fortunately the system still boots via GRUB's 'knetbsd netbsd -v' so
maybe the inability to clear the bootstrap isn't a big deal?


# disklabel output in case it's helpful:
$ disklabel wd0
# /dev/rwd0:
type: ESDI
disk: wd0
label: fictitious
...
4 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 a: 488397168         0     4.2BSD      0     0     0  # (Cyl.      0 - 484520)
 d: 488397168         0     unused      0     0        # (Cyl.      0 - 484520)
disklabel: boot block size 0
disklabel: super block size 0


Unless I'm not using the right filesystem reference I can't think of anything
else to try other than putting NetBSD on a completely separate disk.

-B