SPI and u-boot tweaks on Le Potato Buildroot


I have a Le Potato and I’ve been trying to get a buildroot image together. Here’s what I’ve done so far:

  1. Installed Libre’s buildroot fork from here. (using the 2023.02.x/amlogic branch)
  2. Downloaded the u-boot image file for the amlogic hardware from here and saved it as output/images/u-boot.img
  3. Executed make aml-s905x-cc-v2_defconfig
  4. Compiled the kernel

So far this produces a nice compact initramfs image that appears to UEFI boot into linux. A couple things I’m trying to do and could use some guidance:

  1. SPI isn’t working. I have no /dev/spi* devices at all. Is there a recommended way to get this enabled using Libre Computer’s buildroot repo?

  2. Right now we’re downloading the u-boot image (as described above) and splicing it into the sdcard image. How would we go about tweaking u-boot configuration (either working on device tree configuration, silencing bootloader output) if we’re not compiling it as part of the typical buildroot process?

Any help would be appreciated. The hardware has been fun to tinker with so far.

I think this is what you need to flash the bootloader:

  1. Use the libretech-wiring-tool to enable SPI. You can clone it from GitHub.
  2. You can build your own u-boot from libretech-builder-simple.