arm64 update U-Boot on device (Rock64)

1.) Install Compiler for building U-Boot on our Pine64 Rock64 SBC

sudo apt install device-tree-compiler build-essential libssl-dev python3-dev bison
sudo apt install flex libssl-dev swig gcc-aarch64-linux-gnu gcc-arm-none-eabi
sudo apt install gcc make git

2.) Build U-Boot on our Pine64 Rock64 SBC

cd /home
git clone https://github.com/ARM-software/arm-trusted-firmware
cd arm-trusted-firmware
git tag           (remember last stable --> v2.5 for instance)
git checkout v2.5
make PLAT=rk3328 bl31

cd ..

git clone git://git.denx.de/u-boot.git
cd u-boot
git tag           (remember last stable --> v2021.07 for instance)
git checkout v2021.07
ln -s /home/youruser/arm-trusted-firmware/build/rk3328/release/bl31/bl31.elf bl31.elf
make BL31=bl31.elf rock64-rk3328_defconfig
make -j2 BL31=bl31.elf all u-boot.itb

cd ..

cp -r /home/youruser/u-boot/idbloader.img /home/youruser/
cp -r /home/youruser/u-boot/u-boot.itb /home/youruser/

3.) Flashing U-Boot to our Pine64 Rock64 SBC

cd /home/youruser/

lsblk             (remember storage device name --> mmcblk1 for instance)

sudo dd if=idbloader.img of=/dev/mmcblkX seek=64 conv=notrunc
sudo dd if=u-boot.itb of=/dev/mmcblkX seek=16384 conv=notrunc

4.) Reboot the machine

sudo reboot