U-Boot as ARM Coreboot Payload (for Chromebook Duet)

[Simon Glass]

Hi Dennis,

On Mon, 3 Aug 2020 at 11:08, Dennis Gilmore <dgilmore at fedoraproject.org> wrote:
>
> Simon,
>
> Is there a way to replace the firmware on those boards with u-boot?  I
> have a Tegra, a rockchip, and a pair of Samsung Exynos based
> Chromebooks that are end of life for ChromeOS but are still quite
> useful hardware platforms if there was a way to replace entirely the
> bootloader with u-boot I could have hardware running supported
> operating systems.

Yes you can do that, likely with all of those you mention, although
the Samsung may already use U-Boot.

You can flash an image on the device's command line. The problem is
getting back if you brick it. You need a servo board to be able to
reflash it.

Regards,
Simon

>
> Dennis
>
> On Sun, Aug 2, 2020 at 10:00 PM Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Matthew,
> >
> > On Sun, 2 Aug 2020 at 20:17, Matthew Grochowalski <matt at gwalski.com> wrote:
> > >
> > > Hello,
> > >
> > > Reading https://chromium.googlesource.com/chromiumos/docs/+/master/developer_mode.md,
> > > it appears U-Boot should work as an alternate firmware on new ARM
> > > Chromebooks.
> > >
> > > Trying on my Duet (Kukui/Krane), this doesn't work. Looking at the
> > > RW_LEGACY contents, there's basically nothing there from the factory.
> > >
> > > I tried "make coreboot_defconfig" from u-boot master, but it looks
> > > like this is x86 only.
> > >
> > > Any way to get this working on ARM(64)?
> >
> > I think this is Mediatek and U-Boot doesn't have support for that
> > particular MT part, at least in mainline. I suspect it will happen at
> > some point.
> >
> > The altfw U-Boot feature works on x86 Chromebooks only, at present.
> > That said, most tegra and rockchip Chromebooks support U-Boot running
> > 'bare-metal'.
> >
> > Regards,
> > Simon