Developer Guide for AML-S805X-AC (La Frite)
UARTThe 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.
Vendor SigningAmlogic non-sense to be continued here...
LinuxCurrently, 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.
CompilingFor 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.dtbThis 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.