Thermal printer on Armbian bullseye printing garbage

DevTerm Firmware and Apps
1

In these days I am trying, on my DevTerm A06, to move from the provided OS to Armbian bullseye downloaded from:

It installs fine, seems more responsive and I like it. Only big problem so far is the thermal printer.
Out of the box it’s not working at all. By long searching online I ended up in a configuration that “does something” (prints garbage lines instead of test pattern).
my steps were:

-add deb https://raw.githubusercontent.com/clockworkpi/apt/main/debian/ stable main

-install devterm-audio-patch devterm-fan-daemon-cpi-a06 devterm-gearbox-a06 devterm-thermal-printer devterm-thermal-printer-cups devterm-wiringpi-cpi

-add to /boot/armbianEnv.txt these lines:

overlays=spi-spidev
param_spidev_spi_bus=2
param_spidev_spi_cs=0

At this point I have a device called /dev/spidev2.0, the systemd unit starts fine and printer some sort responds to commands, but not in an useful way.
I have no idea on how to further fix this problem: can someone help me?

Should I also install devterm-kernel-current-cpi-a06 ? (I perfectly know how to manage kernels on desktop PC but no experience at all on embedded)

2

I use a generic file to put things I want to print…

printfile.txt (it is plain text)

print bash notes for thermal printer - external USB:

ls -l /dev/usb/lp0

If the response is something like:

crwxrwxr-x 1 root lp 180, 0 Mar 14 14:11 /dev/usb/lp0

sudo chmod 777 /dev/usb/lp1 (done every boot)

echo -e “This is a test.\n\n\n” > /dev/usb/lp0

echo -e “This is a test.\n\n\n” > /dev/usb/lp1

#prints plane test file full path!!!

cat printfile.txt > /dev/usb/lp0

3

devterm-kernel-current-cpi-a06

should be installed

here is the A06 Os image

http://dl.clockworkpi.com/DevTerm_A06_v0.2h.img.bz2
md5sum 26f52bfde573479960d8696f407d19b9

it is based on armbian