Re: Using a recovery partition to repair a broken installation of FreeBSD

On Mon, 1 Sep 2025 02:58:58 +0100
Graham Perrin <grahamperrin@gmail.com> wrote:

> On 17/08/2025 01:55, Graham Perrin wrote to freebsd-pkgbase:
> 
> > Subject: Using pkgbasify to repair a broken installation of FreeBSD 
> > 14.3-RELEASE
> 
> > <https://gist.github.com/grahamperrin/9570092c127bd43777961b6f016e75ba> 
> 
> 
> The routine is effective, to the best of my knowledge, however it's not 
> particularly attractive. At least:
> 
> - the condensed steps will be too long for some users
> 
> - the first step assumes that the operator will have local access
>    and a USB memory stick.
> 
> I love this response to the Foundation's recent Community Check-In:
> 
>  > … it would be nice to have something like 'recovery partition', as 
> some OSes have. or at least some tiny fail-safe feature. having remote 
> machine in some distant datacenter, booting from a flashstick is always 
> a problem.
> 
> <https://witter.cz/@klokanek/115083259795252616>
> 
> An enhancement to bsdinstall could, before creation of the partition 
> table, allow the user to specify an amount of space to be left free at 
> the end of a device …

On legacy BIOS boots, using MBR (boot0) of FreeBSD allows selecting
which base 4 partition "in the drive" to boot.
So keeping this limitation in mind, rescue partition is possible
and if there's KVM switch accessible via netowork, selections
can be done on boot (not sure about IPMI: no experience).

Currently, both UEFI boot1.efi and loader.efi don't have something
alike "on stock". Ability to choose BE from loader is available,
but IIUC, it can do nothing when the pool itself is causing problem.


On the other hand, boot1.efi has patch to choose partition / pool
to boot at Bug 207940, which is not landed but I'm always using.

  https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=207940

But unfortunately, boot1.efi is deprecated (no expiration target
defined, though) and no merge would be expected.


So it would be nice if loader.efi has this kind of feature.

Implementing with lua and/or forth shouldn't be an option,
as it wouldn't work once the pool / partition loader.efi
looks into is somehow broken.

So should be implemented as the functionality of loader.efi itself and
show its selection menu BEFORE usual boot menu by lua/forth is shown.


-- 
Tomoaki AOKI    <junchoon@dec.sakura.ne.jp>