Re-imaged Raspberry PI Zero 2 W on the system board - now "no serial port found"
My Octoprint web interface had something wrong with it. I have been running it for a while with plugins coming and going - so I created a new Octoprint image on a new microSD.
The new image cannot connect to the printer. It says "No serial port found, are you sure your printer is physically connected and supported? Try refreshing and if that doesn't help please see the FAQ."
It detects and connects fine when I reinstall the old microSD. The hardware is good. Something isn't working on the new image.
Is there some operating system configuration that I'm missing? It has been a long time (years?) since I built an image for the Zero 2 W. I don't remember doing anything special.
RE: Re-imaged Raspberry PI Zero 2 W on the system board - now "no serial port found"
Did you enable the serial interface via raspi-config?
RE: Re-imaged Raspberry PI Zero 2 W on the system board - now "no serial port found"
I tried that and it still didn't work. I compared cmdline.txt and config.txt and got it working.
I'll post what wish I would have found when I ran into this problem.
I re-imaged the Raspberry Pi Zero 2 W installed directly on the Einsy RAMBo main board on my Prusa i3 MK3S printer. No serial ports were detected.
I had forgotten what I had to do in order to get that serial-via-GPIO connection working. Fortunately I reimaged a new microSD card so I could compare my new image with a working image.
To get the serial via GPIO working you must make two edits:
FILE: /boot/cmdline.txt
Retain the existing <YOUR_PARTITION_ID> found existing in this file
console=tty1 root=PARTUUID=<YOUR_PARTITION_ID> rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
FILE: /boot/config.txt
Add this line to the end
enable_uart=1
Result
After rebooting the printer was automatically detected on /dev/ttyS0 at 115200 baud.
There are other forum posts on the internet that change the UART and whatnot, but I couldn't get them to work. I have been using the default/inferior UART for years without issue.
RE: Re-imaged Raspberry PI Zero 2 W on the system board - now "no serial port found"
I dug up my Prusa account I forgot I had just so I could log in and say thank you for this post!
This worked perfectly for me, first try! I don't know how long it would have taken me to figure this out otherwise - thanks so much for sharing this!