"disklabel: Class not found" when editing USB disk

[Tim Judd]

Canonical way to boot FreeBSD by hand, with no tools.  Using one slice, one
partition


fdisk -BI /dev/da0
bsdlabel -Bw /dev/da0s1
newfs /dev/da0s1a

Making sure there's a /boot directory with the all important loader
Making sure /boot/kernel/kernel exists


This should boot -- however is pretty pointless without anything else.
init's needed, and everything else to make a full MUM (Multi User Mode)
environment...


Keep note that not only does the MBR need bootable code, so does the
bsdlabel/disklabel


newfs will set the proper fstype in the bsdlabel if it's partition is 'a'



Good luck... and yes, I top posted.  (Deal with it, people who don't like
it...)


On Thu, Feb 26, 2009 at 10:30 AM, Michael W. Lucas <
mwlucas at blackhelicopters.org> wrote:

> Hi,
>
> I'm following Ceri's instructions for getting FreeBSD on a flash
> drive.  My laptop is a Feb 1 -current, I'm installing FreeBSD 7.1, and
> the instructions are for 6.1, so we have all kinds of things that
> could be going wrong.
>
> The USB boots with the error:
>
> F1 FreeBSD
> F6 PXE
> Boot: F1
>
> Not ufs
> Not ufs
> No /boot/loader
>
> When I investigated the flash's disklabel, I saw:
>
> 8 partitions:
> #        size   offset    fstype   [fsize bsize bps/cpg]
>  a:  4000106       16    unused        0     0
>  c:  4000122        0    unused        0     0         # "raw" part, don't
> edit
>
> I newfs'd this flash drive and put data on it.  The obvious thing to
> do is set the disklabel for partition a to 4.2BSD.  Even if I have to
> reinstall the data, no big deal.
>
> So, run bsdlabel -e /dev/da0s1 and change the disklabel to:
>
> #        size   offset    fstype   [fsize bsize bps/cpg]
>  a:  4000106       16    4.2BSD        0     0
>  c:  4000122        0    unused        0     0         # "raw" part, don't
> edit
>
> Then I get the error:
>
> bsdlabel: Class not found
> re-edit the label? [y]:
>
> The same error appears if I try to edit the disklabel off-disk and
> restore (-R).
>
> Google tells me that this error is not uncommon, but the only
> solutions I saw (loading geom_mbr and setting kern.geom.debugflags=16)
> did not help.
>
> Anyone have any suggestions?  Or, can anyone tell me I'm running down
> the wrong path?
>
> Thanks,
> ==ml
>
> --
> Michael W. Lucas        mwlucas at BlackHelicopters.org, mwlucas at FreeBSD.org
> http://www.BlackHelicopters.org/~mwlucas/<http://www.BlackHelicopters.org/%7Emwlucas/>
> Latest book:  Cisco Routers for the Desperate, 2nd Edition
> http://www.CiscoRoutersForTheDesperate.com/
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