Re: installboot: Old BPB too big, use -f (may invalidate filesystem)

[Martin Husemann <martin%duskware.de@localhost>]

On Mon, Feb 14, 2022 at 07:25:37PM +0100, Edgar Fuß wrote:
> What does
> 	installboot: Old BPB too big, use -f (may invalidate filesystem)
> mean?
> 
> I have a RAIDframe level 1 RAID consisting of /dev/sd0e and /dev/sd1e.
> Now, sd0 failed. I replaced the disc, fdisk'ed and disklabel'ed it and 
> performed a raidctl -R, which succeeded. Now, I need to write the boot 
> code, so I can boot from the new disc. But installboot /dev/rsd0e 
> /usr/mdec/bootxx_ffsv1 gives me above error message.
> I tried installboot -n /dev/rsd1e /usr/mdec/bootxx_ffsv1, which works.

BPB = a special block in a FAT (or NTFS) file system [BIOS Parameter Block],
often within the first 8k of the partition so it may collide with the
primary boot code installboot is trying to write there.

Installboot on x86 has special checks to avoid destructing such a file system
when adding our primary boot code on systems that dual boot into NetBSD
and windows.

If you are trying to setup the machine for NetBSD only use, you don't really
have to care unless you are booting from a FAT file system. But in usual
setups this should not happen and something else may be wrong:

 - if you are UEFI booting from a FAT partition, you do not need any
   boot blocks installed (don't do the installboot at all), you just need
   to copy /usr/mdec/*.efi to /EFI/BOOT/ on the FAT partition.

 - if you really want ffsv1 boot code, then sd0e better not be a FAT file
   system

Martin