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These instructions document how FreeBSD (head) can be built for, and installed on the Helios-4. This has been made possible by the initial port of FreeBSD to the SolidRun Clearfog that has been submitted June 2017 by Semihalf and Stormshield: Read the announcement here.

Compiling FreeBSD

There is a manual way to compile FreeBSD, and it is documented on the SolidRun Wiki Clearfog page. The process is almost identical for the Helios-4 in that a suitable DTB has to be copied to the boot partition. The following instructions use the crochet utility for automating the build and imaging process.

Get the source

We use a fork of crochet that has added the necessary bits for Helios-4.

mkdir work; cd work
git clone --checkout pr-clearfog
svn checkout src

Configure the build

crochet uses a configuration file to perform builds. is an example, and can be adapted as needed. As a bare minimum, a line

board_setup Clearfog

has to be at the top near the other commented board_setup_* lines. In addition enabling the growfs feature has proven useful for autoresizing the rootfs on first boot: simply uncomment the line

option Growfs

There are plenty of other settings to change, but these suffice for creating a bootable image.


Navigate to the crochet folder, and assuming you called your config file, run:

sudo /bin/sh -c

On success an sdcard image will have been produced in the build directory, for example /opt/work/build/FreeBSD-armv7-12.0-GENERIC-333641-Clearfog.img. This image is a complete FreeBSD installation, without U-Boot installed.

Create SD-Card

The previously created image can be written to an sdcard as is; assuming your SD-Card is available at /dev/sdX, write the image to it:

pv FreeBSD-armv7-12.0-GENERIC-333641-Clearfog.img | sudo tee /dev/sdX >/dev/null

Boot It

In an ideal world U-Boot would already be installed in SPI flash, including the necessary patch for FreeBSD. If you happen to have such an ideal system, you may skip the next section

Install U-Boot

Please refer to U-boot for build instructions.

The Boot-ROM expects to find U-Boot at 512 bytes into the sdcard. Assuming your SD-Card is available at /dev/sdX, write the u-boot binary to it using dd:

sudo dd bs=512 seek=1 conv=fsync if=u-boot-a38x-5-15-mmc.bin of=/dev/sdX


Insert the sd-card into your device, connect a serial console and turn it on. The U-Boot console will come up with a prompt:

Hit any key to stop autoboot: 3

Press a key to abort automatic boot, or wait till it fails to do a network boot. Once it has dropped to a terminal prompt, indicated by Marvell>> at the start of the line, configure U-Boot to load the FreeBSD loader by default:

setenv fdt_addr_r 0x1000000
setenv loadaddr 0x2000000
setenv bootcmd 'fatload mmc 0:2 ${fdt_addr_r} armada-388-helios4.dtb; fatload mmc 0:2 ${loadaddr} ubldr.bin; go ${loadaddr}'
setenv bootdelay 1

Beware: You probably have to paste these lines individually, or U-Boot may mess it up. You can set bootdelay to 0 if you want, that way you will never again get to the u-boot console unless you delete the FreeBSD loader.

Finally, type boot, or reset, or reset the board by pressing the button labeled U16 on the board. This time, just sit back and watch as FreeBSD comes up.

Default User

The FreeBSD image by crochet comes with an unlocked root account. This means you do not need to enter a password to log in as root.

Page contributed by Artox

Last update: May 2, 2020