Basically, we have to follow only https://elinux.org/RPi_U-Boot
Make u-boot on Ubuntu 18.04
Create u-boot.bin from source code.
git clone git://git.denx.de/u-boot.git
cd u-boot
sudo apt install gcc-arm-linux-gnueabi
sudo apt install gcc-aarch64-linux-gnu
export CROSS_COMPILE=aarch64-linux-gnu-
make rpi_3_defconfig
make -j1 -s
sudo cp u-boot.bin /media/user/boot/kernel8.img
Copy u-boot image to SD micro card.
Copy u-boot image to boot partition as kernel8.img.
SD card is already installed raspbian.
sudo cp u-boot.bin /media/user/boot/kernel8.img
Connect Rapsberry Pi 3 and PC
Raspberry Pi 3 B pin assign is as following
- PIN 6 GND
- PIN 8 TX
- PIN10 TX
We should confirm boot raspbian and enable GPIO.
Serial Setting on PC
- Boolate: 115200
- data: 8bit
- parity: None
- Stop: 1bit
- Flow control: Nonee
After Raspberry Pi boot, We can find u-boot pronto on serial port.