APU2 APU3 APU4 BIOS upgrade

PC Engines publishes a new BIOS for the APU, every 4-8 weeks. Some recent BIOS versions added better suppoer for ECC Ram, and cpu boost to 1.4Ghz therefore it's worth to upgrade.

Download the latest BIOS versions here: https://pcengines.github.io/

Method 1: flash bios from pfSense

If you have pfSense installed on your router, this is the easier method to use.

Step 1: install flashrom utility

In pfSense web UI, go to Diagnostics -> Command Prompt

Under "Execute Shell Command" type

pkg install -y flashrom

and click Execute.

Step 2: Download bios your file to your computer.

Get bios file from here: https://pcengines.github.io/

Now upload the file from your computer to the pfsense using "Upload File" under Diagnostics -> Command Prompt

Notice your file will be uploaded to /tmp/

Step 3: unpack the file

Some BIOS versions come packaged in in .tar.gz. some come directly as .rom

If file you have packaged file, you fill have to extract the .rom first.

To unpack your file issue the following command under "Execute Shell Command".

tar -xvf /tmp/apu4_v4.6.10.rom.tar.gz

You will see something like this

Shell Output - tar -xvf /tmp/apu4_v4.6.10.rom.tar.gz
tar: Failed to set default locale
x apu4_v4.6.10.rom
x apu4_v4.6.10.rom.md5

Step 4: Flash bios

Now Under "Execute Shell Command" type

flashrom -w /tmp/apu4_v4.6.10.rom -p internal:boardmismatch=force

You will see something like this

Shell Output -
flashrom v1.0 on FreeBSD 11.2-RELEASE-p6 (amd64)
flashrom is free software, get the source code at https://flashrom.org
Using clock_gettime for delay loops (clk_id: 4, resolution: 2ns).
coreboot table found at 0xcffd5000.
Found chipset "AMD FCH".
Enabling flash write... OK.
Found Winbond flash chip "W25Q64.V" (8192 kB, SPI) mapped at physical address 0x00000000ff800000.
Reading flash... done.

Reboot your router.

Method 2: Flash bios from debian

If you don't have pfSense installed, use this method.

Step 1: create a bootable USB stick

You can create a bootable debian stick, like described here: Debian installation instructions or another linux distribution of your choosing. The important step is to be able to boot linux that has flashrom utility.

Step 2: install flashrom

If you have a bootable debian, you can simply install flashrom from the repository

sudo apt-get install flashrom

otherwise, install flashrom some other way.

Step 3: download BIOS version for your board

Download the latest BIOS versions here: https://pcengines.github.io/

Make sure you download the correct version. If you have APU3, make sure you download APU3 image.

wget http://pcengines.ch/file/apu3_v4.8.0.5.rom.tar.gz

gunzip apu3_v4.8.0.5.rom.tar.gz

ls -l apu3_v4.8.0.5.rom

Make sure you unpack the image like shown above. You need a file with .rom extension.

Step 4: write the new BIOS to the chip

Use the below command, make sure you replace the image name with the image you downloaded.

flashrom -w apu3_v4.8.0.5.rom -p internal:boardmismatch=force

Here's how it should look like, if you have done it correctly.

root@debian:~# flashrom -w apu3_v4.8.0.5.rom -p internal:boardmismatch=force
flashrom v0.9.9-r1954 on Linux 4.9.0-6-amd64 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

Calibrating delay loop... OK.
coreboot table found at 0xcfed1000.
Found chipset "AMD FCH".
Enabling flash write... OK.
Found Winbond flash chip "W25Q64.V" (8192 kB, SPI) mapped at physical address 0x00000000ff800000.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... VERIFIED.

All ready! Reboot and enjoy new BIOS!

Troubleshooting.

If, somehow, you managed to write a wrong BIOS to the board, or you lost electricity during the upgrade, you can recover with the BIOS flash recovery module.

We have flashed hundreds of BIOSes on these boards and never needed this module. Don't buy it ahead of time :-)

Tip: check out many similar articles in our Knowledge Base.