Developer Guide for AML-S805X-AC (La Frite)

loverpi

UART

The board features standard 3.3V UART on the 40 pin header. Pin 1 is closest to the IR sensor and pin 39 is closest to the HDMI connector. If you are using one of the dirt cheap UART dongles, you can connect the color coded wires based on the graphic below:

The baud rate is 115200 8N1. minicom -b 115200 -D /dev/ttyUSB0. Disable flow control by pressing Control + A, O, Serial port setup, F.

u-boot

libretech_ac_defconfig

Vendor Signing

Amlogic non-sense to be continued here...

Linux

Currently, there are 3 recommended kernels depending on your needs: Mainline LTS 5.4 Stable 5.3 LTS 4.19 + Patches
We try to use the latest Linux LTS release which is currently 4.19 but will be transitioning to 5.4 as it is released in Q4 2019. Linux 4.19 LTS will not work out of the box so we have out of tree patches. Linux 5.4 should work out of the box for everything except audio, USB device mode, and DRM planes.

Compiling

For cross compiling the kernel on x86, clone the appropriate git repository and generate a dtb and deb via:

make ARCH=arm64 defconfig
make CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm64 -j `nproc` deb-pkg amlogic/meson-gxl-s805x-libretech-ac.dtb

This will have a lot fewer built-ins and modules than the kernel we use but it is a starting point. Make sure to compile btrfs into the kernel as a built-in since the root file system needs to be readable. Make sure that EFI stub is enabled so that grub-efi-arm64 is capable of starting the kernel.

Documentation

linux-meson.com

Resources

Freenode #linux-amlogic
Freenode #librecomputer

crocket

Linux 5.4 was released.