Getting the Raspberry Pi Zero 2 working on Prusa MK3S

I'm writing the post I wish I would have found when I ran into this problem. It already includes the answer that worked for me.

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 rootwait

FILE: /boot/config.txt

add this line to the end


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.

1 Like

You don't need to manually edit anything. Ssh to the pi and run sudo raspi-config
Under interfacing go to serial. The first question is do you want a login console. Answer no. The second is do you want the serial hardware enabled. Answer yes
Exit and answer yes to reboot