Setting up Pi4J for RISC-V

RISC-V is an open, royalty-free instruction set architecture, and boards built around it are becoming more common as alternatives to ARM-based SBCs. This page collects what’s needed to get Java and Pi4J running on RISC-V hardware.

Tested boards

1. Milk-V Mars

Installing JDK 25+

There aren’t many builds of Java for the RISC-V architecture yet, so we recommend installing it from the Adoptium project:

sudo apt install -y wget apt-transport-https gpg
wget -qO - https://packages.adoptium.net/artifactory/api/gpg/key/public | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/adoptium.gpg > /dev/null
echo "deb https://packages.adoptium.net/artifactory/deb $(awk -F= '/^VERSION_CODENAME/{print$2}' /etc/os-release) main" | sudo tee /etc/apt/sources.list.d/adoptium.list
sudo apt update
sudo apt install temurin-25-jdk

Board Details

Milk-V Mars

1. Download the Ubuntu image from Canonical: ubuntu-24.04.4-preinstalled-server-riscv64+jh7110.img.xz

2. Flash the Ubuntu image to an SD card, as described in Canonical’s flashing guide (or use Balena Etcher).

3. Connect UART from your PC to the Milk-V Mars, following Canonical’s UART console instructions.

4. Open the UART console on your PC and press any key when the message “Hit any key to stop autoboot” appears.

5. Run the following commands:

   sf probe
   load mmc 1:1 $kernel_addr_r /usr/lib/u-boot/starfive_visionfive2/u-boot-spl.bin.normal.out
   sf update $kernel_addr_r 0 $filesize
   load mmc 1:1 $kernel_addr_r /usr/lib/u-boot/starfive_visionfive2/u-boot.itb
   sf update $kernel_addr_r 0x100000 $filesize
   reset
   

6. Press any key again when the message “Hit any key to stop autoboot” reappears.

7. Run the following commands:

   env default -f -a
   env save
   reset
   

8. After the reboot, you’ll see the boot process in the UART console. Once you see the “login” prompt, log in as ubuntu:ubuntu.

9. Have fun!