Running 64-bit RISC-V Linux on SiFive HiFive Unleashed

SiFive’s HiFive Unleashed is a Linux capable development board featuring the Freedom U540, the industry’s first commercially available Linux-capable RISC-V SoC.

It’s a very good starting point if you want to get Linux running on a physical chip/board. Just like with the HiFive1, SiFive provides open source schematics, an Altium Designer PCB project, BOM, and - of course - tooling for the HiFive Unleashed.


Fig. 3 The HiFive Unleashed board - top.


This chapter targets Debian-based Linux flavors, and has been tested on Ubuntu 18.04.


Running Linux on the HiFive Unleashed board requires you to install some prerequisites.

sudo apt install autoconf automake autotools-dev bc bison build-essential curl flex \
                 gawk gdisk git gperf libgmp-dev libmpc-dev libmpfr-dev libncurses-dev \
                 libssl-dev libtool patchutils python screen texinfo unzip zlib1g-dev

Getting the sources

Clone the official Freedom Unleashed SDK repository and checkout to appropriate version:

git clone --recursive
cd freedom-u-sdk
git checkout hifive-unleashed
cd buildroot
git checkout sifive
cd ..


Recursively cloning the Freedom Unleashed SDK repository may take a while. Should it fail, use git submodule update --init --recursive inside the freedom-u-sdk folder to make sure you have all the relevant files.


Simply run:

make -j $(nproc)


The build process may take some time, do not be discouraged by the wait.


Insert an empty SD card and run the following commands:

umount /dev/sdx     # change "x" hereinafter with a letter corresponding to your SD card!
sgdisk --clear \
       --new=1:2048:67583  --change-name=1:bootloader --typecode=1:2E54B353-1271-4842-806F-E436D6AF6985 \
       --new=2:264192:     --change-name=2:root       --typecode=2:0FC63DAF-8483-4772-8E79-3D69D8477DE4 \
dd if=freedom-u-sdk/work/bbl.bin of=/dev/sdx1 bs=4096
mke2fs -t ext3 /dev/sdx2


Connect HiFive’s USB serial console to your PC. On the PC, open your favourite serial terminal and connect to the board’s serial console using e.g picocom:

picocom -b 115200 /dev/ttyUSBX
# where X is the device number - this can be obtained from e.g. your system log


The UART connection parameters are: baud rate 115200 bps, no flow control, 8bit words, no parity bits. The /dev/ttyX device may not appear in the system until the HiFive board is powered.

Power up the board and wait until Linux boots. The default Linux credentials are: