Chris Ross <cross+netbsd%distal.com@localhost> writes:
> On May 9, 2009, at 17:00, Aleksey Cheusov wrote:
>>> copy the new boot to /boot from /usr/mdec/boot and install your
>>> respective bootblocks via installboot.
>> I didn't do this while doing source-based upgrade 3.0/4.0 and 4.0/5.0
>> and everything work just fine.
>> Is this really necessary?
>
> I suspect it depends on what, if any, significant changes were made
> in /boot and/or the boot blocks. Which will depend, at least, on your
> platform, and perhaps even your hardware, as to whether or not the
> changes are "necessary".
>
> I suspect it's just the wise thing to do, even when not needed.
It is definitely the wise thing to do.
Boot blocks change occasionally in terms of what they can cope with, and
it's pretty gradual. You can easily end up with a 3.0 system with 1.6
bootblocks - I did. On sparc (slightly fuzzy on details of numbers),
this works ok. But when you try to boot a 4.0 kernel it won't work,
because there's a change made to the boot/kernel interface. I do not
really remember if up-to-date netbsd-3 boot code works with 4.0 or if
you have to install the boot code and the kernel at the same time. All
of my psparc/sparc64 boxes are now >= 4.
So I am now trying to be very careful about keeping bootblocks up to
date.
I am 99% sure that you can on i386 upgrade to 5.0 with 4.0 bootblocks
and then update the bootblocks. If you have console access it's
reasonably easy to just testboot a new kernel.
You can figure this out by reading CVS history, more or less.
I think it would be nice if any new {xxboot bootxx /boot} features are
needed to boot a new kernel that the features be pulled up to release-N
before being used in N.99 or N+1.0 But I realize that's a perhaps big
request.
Comments about not having new features are also a good reason to
upgrade, but for me the big deal is being able to boot the new kernel
with the older bootblocks and not lose.
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