U-Boot for Radxa Zero2 (A311D)
Radxa Zero2 is a small form factor SBC based on the Amlogic A311D chipset with the following specification:
Amlogic A311D (Quad A73 + Dual A53) CPU
4GB LPDDR4 RAM
32/64/128GB eMMC
Mali G52-MP4 GPU
HDMI 2.1 output (micro)
BCM4345 WiFi (2.4/5GHz a/b/g/n/ac) and BT 5.0
1x USB 2.0 port - Type C (OTG)
1x USB 3.0 port - Type C (Host)
1x micro SD Card slot
40 Pin GPIO header
Schematics are available on request from Radxa.
U-Boot Compilation
$ export CROSS_COMPILE=aarch64-none-elf-
$ make radxa-zero2_defconfig
$ make
U-Boot Signing with Pre-Built FIP repo
$ git clone https://github.com/LibreELEC/amlogic-boot-fip --depth=1
$ cd amlogic-boot-fip
$ mkdir my-output-dir
$ ./build-fip.sh radxa-zero2 /path/to/u-boot/u-boot.bin my-output-dir
U-Boot Manual Signing
Amlogic does not provide sources for the firmware and tools needed to create a bootloader image so it is necessary to obtain binaries from sources published by the board vendor:
$ git clone -b radxa-zero-v2021.07 https://github.com/radxa/u-boot.git
$ git clone https://github.com/radxa/fip.git
$ sudo apt-get install -y gcc-aarch64-linux-gnu device-tree-compiler libncurses5 libncurses5-dev
$ sudo apt-get install -y bc python dosfstools flex build-essential libssl-dev mtools
$ wget https://developer.arm.com/-/media/Files/downloads/gnu-a/10.3-2021.07/binrel/gcc-arm-10.3-2021.07-x86_64-aarch64-none-elf.tar.xz
$ sudo tar xvf gcc-arm-10.3-2021.07-x86_64-aarch64-none-elf.tar.xz -C /opt
$ export CROSS_COMPILE=/opt/gcc-arm-10.2-2020.11-x86_64-aarch64-none-elf/bin/aarch64-none-elf-
$ export ARCH=arm
$ cd u-boot
$ make radxa-zero2_defconfig
$ make
$ cp u-boot.bin ../fip/radxa-zero2/bl33.bin
$ cd ../fip/radxa-zero2
$ make
This will generate the signed U-Boot binaries:
$ u-boot.bin u-boot.bin.sd.bin u-boot.bin.usb.bl2 u-boot.bin.usb.tpl
Then write U-Boot to SD or eMMC with:
$ DEV=/dev/boot_device
$ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=512 skip=1 seek=1
$ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=1 count=440