nanobsd boot slice selection does not work

[Paul Schenkeveld]

On Mon, May 11, 2009 at 09:40:31AM -0400, John Baldwin wrote:
> On Tuesday 05 May 2009 10:49:38 am Paul Schenkeveld wrote:
> > On Mon, Apr 20, 2009 at 03:55:23PM +0200, Matthias Teege wrote:
> > > Moin,
> > > 
> > > > I've seen this problem as well, but can't for the life of me remember 
> what I 
> > > 
> > > I'm relieved to hear that.
> > 
> > Ok, a bit late (interrupt storm generated by device $WORK) but I just
> > tested with a clean 7.2-RELEASE source tree.  I too can report this
> > regression in boot0 which now looks at the active flag in a MBR table
> > entry instead of its own default partition byte when not choosing the
> > partition by pressing 1 or 2 at the prompt.  This is a regression.
> > 
> > The boot0 source code appears to have had a complete overhaul between
> > 7.1 and 7.2.
> > 
> > As a workaround, use the 7.1 boot0 source (or even use 7.1 completely
> > if you care about the anticipated eol of the release).
> > 
> > I hope Luigi will have some time to look at the default drive delection
> > algorithm again zome time soon.
> 
> I think you can simply re-enable the 'update' flag using boot0cfg in 7.2 to 
> fix this?

The update flag is on, besides it controls whether the first sector is
written back or not after selecting another slice than the default using
the keyboard.  The problem above shows that the 'default' slice variable
in sector 0 is not read anymore but the MBR records are searched for
an active flag.  Using the (M$DOS-compatible) active flag only slices
1-4 can be set as default, the boot0 default variable also allows for
selection 5 (next disk) and probably also 6 (pxe boot) to be saved as
default.

-- Paul Schenkeveld