Re: [PATCH v6 09/11] doc: spacemit: flash on K1 SoC based boards

[Yao Zi <me@ziyao.cc>]

On Tue, Jul 28, 2026 at 08:53:02AM +0800, Eric Chung wrote:
> On Tue, Jul 28, 2026 at 1:26 AM Yao Zi <me@ziyao.cc> wrote:
> >
> > On Mon, Jul 27, 2026 at 02:59:11PM +0800, Eric Chung wrote:
> > > Add document on how to flash images into eMMC of K1 SoC based boards.
> > >
> > > Signed-off-by: Eric Chung <eric.chung@riscstar.com>
> > >
> > > ---
> > > v3:
> > > - Add document on how to flash images into SD card.
> > > ---
> > >  board/spacemit/k1/MAINTAINERS |   2 +-
> > >  doc/board/spacemit/index.rst  |   1 +
> > >  doc/board/spacemit/k1-mmc.rst | 320 ++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 322 insertions(+), 1 deletion(-)
> >
> > ...
> >
> > > diff --git a/doc/board/spacemit/k1-mmc.rst b/doc/board/spacemit/k1-mmc.rst
> > > new file mode 100644
> > > index 00000000000..b0fe78c75ce
> > > --- /dev/null
> > > +++ b/doc/board/spacemit/k1-mmc.rst
> > > @@ -0,0 +1,320 @@
> >
> > ...
> >
> > > +Chapter 2: SD Card Boot
> > > +=======================
> > > +
> > > +
> > > +SpacemiT K1 Bianbu SD Card Image Flashing and U-Boot Update Guide
> > > +==================================================================
> > > +
> > > +This guide explains how to prepare a bootable SD card with Bianbu OS for
> > > +SpacemiT K1 based boards and how to replace the U-Boot binary on the SD
> > > +card with a custom build.
> > > +
> > > +Prerequisites
> > > +~~~~~~~~~~~~~
> > > +
> > > +- A SpacemiT K1 based development board
> > > +- A microSD card (at least 8 GB capacity recommended)
> > > +- A card reader for your host computer
> > > +- A Linux host system (for ``dd``, ``fdisk``, ``lsblk`` commands)
> > > +- The Bianbu SD card image from
> > > +   <https://spacemit.com/community/resources-download/Images%20Collects/K1/Bianbu>
> > > +- A custom ``u-boot.itb`` file (device tree blob or U-Boot FIT image) to be
> > > +  written to the U-Boot partition
> > > +
> > > +Prepare the SD Card & the image
> > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > +
> > > +**1. Download the image**
> > > +
> > > +Download the released package from the official SpacemiT website:
> > > +
> > > +<https://archive.spacemit.com/image/k1/version/bianbu/v2.3.5/Bianbu-Minimal-K1-sdcard-V2.3.5-20260601180942.img.zip>
> > > +
> > > +**2. Extract the image**
> > > +
> > > +.. code-block:: console
> > > +
> > > +   $ unzip Bianbu-Minimal-K1-sdcard-V2.3.5-20260601180942.img.zip
> > > +
> > > +**3. Identify the SD card device**
> > > +
> > > +Insert the microSD card into your card reader, then run:
> > > +
> > > +.. code-block:: console
> > > +
> > > +   $ lsblk
> > > +
> > > +Compare the output before and after inserting the card to identify
> > > +the new device. It will typically appear as ``/dev/sdb``, ``/dev/sdc``,
> > > +or ``/dev/mmcblk0``.
> > > +
> > > +**4. Write the image to the SD card**
> > > +
> > > +.. code-block:: console
> > > +
> > > +   $ sudo dd if=./Bianbu-Minimal-K1-sdcard-V2.3.5-20260601180942.img of=/dev/sdb bs=1M status=progress
> > > +
> > > +The SD card is now ready as a bootable Bianbu system disk.
> >
> > This looks out of scope of describing how to create a bootable SD card
> > with U-Boot. In my opinion, you'd better describe the requirements of
> > parition layout and image position for SD-card booting, to allow readers
> > to create their own images/bootable medium from scratch more easily,
> > instead of sticking to the vendored image.
> >
> 
> Creating a bootable SD card from scratch would be valuable, but I'll address
> it later due to time constraints.

In case I didn't make myself clear enough, the documentation *SHOULD*
describe how to create bootable devices from scratch, instead of
alternating an existing OS image to use mainline U-Boot. I don't think
the current documentation helps much for downstream users/distributions
to adapt U-Boot for their own use cases, or at least it could be written
in a much more clear, vendor-neutral way.

So here's my NAK for this patch. I'm not sure what you mean by "time
constraints", but please keep submitted patches in a good shape.

Thanks,
Yao Zi