[PATCH 0/7] pxe_utils: small fixups, implement BLS type 1 boot on top of them

[Alexey Charkov]

On Thu, Jun 4, 2026 at 9:21 PM Tom Rini <trini at konsulko.com> wrote:
>
> On Thu, Jun 04, 2026 at 09:16:58PM +0400, Alexey Charkov wrote:
> > On Thu, Jun 4, 2026 at 8:05 PM Tom Rini <trini at konsulko.com> wrote:
> > >
> > > On Thu, Jun 04, 2026 at 07:31:05PM +0400, Alexey Charkov wrote:
> > >
> > > > Add support for the Boot Loader Specification (BLS) type 1 boot entries,
> > > > as generated by default by systemd's kernel-install when loader=bls.
> > > >
> > > > Given that the format of BLS entries is pretty much the same as PXElinux,
> > > > reuse the existing library for the parsing logic.
> > > >
> > > > BLS type 2 entries are out of scope, as they are effectively just EFI
> > > > applications and should be booted as such.
> > > >
> > > > This implementation is also only allowing a single top-sorting entry to
> > > > boot, as the standard boot infrastruture currently doesn't support
> > > > multiple entries per partition-bootmeth tuple. I have a proposed extension
> > > > to enable that and will post it separately as RFC - that enables the use
> > > > of `bootflow menu` to select the kernel to boot without jumping through
> > > > several menus with different behavior as is currently required with
> > > > extlinux.conf.
> > > >
> > > > Signed-off-by: Alexey Charkov <alchark at flipper.net>
> > >
> > > This is good to see, thanks for posting it. One concern I have is that
> > > out of 1529 platforms, this would be enabled on 1392 of them. And the
> > > size growth is around 1.5 kilobytes. Is there some smaller percentage of
> > > platforms this should be "default y" for ? Or is the expectation that
> > > something like Debian will be configuring for this moving forward, so
> > > yes even something like PowerPC platforms be using this? Thanks!
> >
> > Well this is the config format that systemd's kernel-install produces
> > out of the box, and it doesn't require EFI support unlike UKI (a.k.a.
> > BLS type 2). So one could argue that any system shipping with systemd
> > benefits directly. In my view, that makes it more accessible for end
> > users than e.g. bootmeth_extlinux, which is also "default y" but I
> > could only find a suitable config generator for it with device tree
> > support in Debian (not in Fedora, nor in Gentoo out of my extremely
> > representative sample of N=3 distros).
> >
> > Happy to make it conditional on whatever platforms find this helpful
> > though, or drop "default y" altogether. I personally only care about
> > ARM, and Rockchip in particular :)
>
> Right. What I'm asking is, do you know how many distros are planning to
> adopt BLS type 1 support by default? And since you're on Rockchip, why
> not just use BLS type 2?

I've only seen Fedora use it by default, but I'm not that much of a
distro connoisseur. There might be more, or there might not.

BLS type 2 didn't work for me last time I tried it because it
seemingly wanted to bake the DTB into the UKI and couldn't handle DT
overlays, which made booting different boards with the same kernel
binary a pain. BLS type 1 didn't have those issues, and a concise
plaintext config has its (subjective) appeal over
yet-another-packed-binary-format.

Best regards,
Alexey