In some programs like screen I couldn't figure out, how to correctly display line endings. With picocom it works. A bit too much new lines but the content is readable.

# picocom -b 115200 --imap crcrlf /dev/ttyUSB0

Install flashrom.

[2.4.1-RELEASE][admin@pfSense]/root: pkg install flashrom
Updating pfSense-core repository catalogue...
pfSense-core repository is up to date.
Updating pfSense repository catalogue...
pfSense repository is up to date.
All repositories are up to date.
The following 3 package(s) will be affected (of 0 checked):

New packages to be INSTALLED:
        flashrom: 0.9.9_2 [pfSense]
        libpci: 3.5.5 [pfSense]
        pciids: 20170916 [pfSense]

Number of packages to be installed: 3

The process will require 2 MiB more space.
381 KiB to be downloaded.

Proceed with this action? [y/N]: y
[1/3] Fetching flashrom-0.9.9_2.txz: 100%  143 KiB 146.0kB/s    00:01
[2/3] Fetching libpci-3.5.5.txz: 100%   49 KiB  49.9kB/s    00:01
[3/3] Fetching pciids-20170916.txz: 100%  190 KiB 194.4kB/s    00:01
Checking integrity... done (0 conflicting)
[1/3] Installing pciids-20170916...
[1/3] Extracting pciids-20170916: 100%
[2/3] Installing libpci-3.5.5...
[2/3] Extracting libpci-3.5.5: 100%
[3/3] Installing flashrom-0.9.9_2...
Extracting flashrom-0.9.9_2: 100%
[2.4.1-RELEASE][admin@pfSense]/root:

Download firmware.

[2.4.1-RELEASE][admin@pfSense]/root: cd /tmp/
[2.4.1-RELEASE][admin@pfSense]/tmp: fetch http://pcengines.ch/file/apu2_v4.0.7.rom.zip
apu2_v4.0.7.rom.zip                           100% of  726 kB 1156 kBps 00m00s
[2.4.1-RELEASE][admin@pfSense]/tmp: unzip apu2_v4.0.7.rom.zip
Archive:  apu2_v4.0.7.rom.zip
 extracting: apu2_v4.0.7.rom
 extracting: apu2_v4.0.7.rom.md5
 extracting: changes.txt

Install firmware.

[2.4.1-RELEASE][admin@pfSense]/tmp: flashrom -w apu2_v4.0.7.rom -p internal
flashrom v0.9.9-r1955 on FreeBSD 10.3-RELEASE-p5 (amd64)
flashrom is free software, get the source code at https://flashrom.org

Calibrating delay loop... OK.
coreboot table found at 0xdffae000.
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.

PC Engines: BIOS Update

With pfSense 2.3 and later pkg can be used to install software.according to the documentation it's not recommended

With NanoBSD image (deprecated):

[2.3.2-RELEASE][root@pfSense]/root: /etc/rc.conf_mount_rw
[2.3.2-RELEASE][root@pfSense]/root: pkg install flashrom-0.9.9
[2.3.2-RELEASE][root@pfSense]/root: /etc/rc.conf_mount_ro

With normal image:

[2.3.2-RELEASE][root@pfSense]/root: pkg install flashrom-0.9.9

[2.3.2-RELEASE][root@pfSense]/root: flashrom -w apu2_160311.rom -p internal
flashrom v0.9.9-r1955 on FreeBSD 10.3-RELEASE-p5 (amd64)
flashrom is free software, get the source code at https://flashrom.org

Calibrating delay loop... OK.
coreboot table found at 0xdffae000.
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.

• HAProxy setup for acme plugin