On Tue, Jul 28, 2026 at 5:45 PM Yao Zi <[email protected]> wrote: > > On Tue, Jul 28, 2026 at 08:53:02AM +0800, Eric Chung wrote: > > On Tue, Jul 28, 2026 at 1:26 AM Yao Zi <[email protected]> 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 <[email protected]> > > > > > > > > --- > > > > 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. >
I’m not sure why the documentation insists on walking users through creating a bootable SD card from scratch, especially when, at this stage, it still depends on the vendor’s tools. In practice, we’re required to use the vendor’s flashing tool for both eMMC and SD devices, and we must adhere to the provided partition table. If users prefer to define their own partition layout, nothing prevents them from doing so on their own. That’s entirely up to them. The default SD image already includes the vendor’s U-Boot. My instructions simply explain how to replace it with the upstream version—nothing more.
