What is the problem?
New SD card, fresh install using the latest Pi Imager downloaded today 25 May 2022).
Set up Geeetech A20 printer (255x255x250, front left origin, heated bed).
Select AUTO for all connections and click Connect.
Printer resets (!) then connects then immediately starts lowering head to print bed (with a grinding sound from the stepper).
Ignores the BLTouch probe and continues down, crashing the hot end into the print bed and then attempting to continue lowering until I power off the printer.
The terminal log shows this command response from the printer:
Unknown command: "ª\x19\x10"
Absolutely repeatable every time.
What did you already try to solve it?
Reset connection.
Checked Z-offset (correct)
Ran BLTouch self test (passed)
Reimaged card and re-setup.
Problem remains.
Have you tried running in safe mode?
Yes, in safe mode the behaviour is different but still odd.
Did running in safe mode solve the problem?
Hit Connect
Printer resets ()
Octoprint connects
Hot end raises around 15mm (I was too busy watching the hot end to note the exact head position on the display)
Head stops (no lowering into print bed)
Terminal interface shows repeating list of the message:
Unknown command: "ª\x19\x10"
Systeminfo Bundle
browser.user_agent : Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36 OPR/86.0.4363.59
connectivity.connection_check : 1.1.1.1:53
connectivity.connection_ok : true
connectivity.enabled : false
connectivity.online : true
connectivity.resolution_check : octoprint.org
connectivity.resolution_ok : true
env.hardware.cores : 4
env.hardware.freq : 1400
env.hardware.ram : 914006016
env.os.bits : 32
env.os.id : linux
env.os.platform : linux
env.plugins.pi_support.model : Raspberry Pi 3 Model B Plus Rev 1.3
env.plugins.pi_support.octopi_version : 0.18.0
env.plugins.pi_support.octopiuptodate_build : 0.18.0-1.8.1-20220524101555
env.plugins.pi_support.throttle_state : 0x0
env.python.pip : 20.3.3
env.python.version : 3.7.3
env.python.virtualenv : true
octoprint.last_safe_mode.date : 2022-05-25T09:11:42Z
octoprint.last_safe_mode.reason : settings
octoprint.safe_mode : true
octoprint.version : 1.8.1
systeminfo.generated : 2022-05-25T09:16:47Z
systeminfo.generator : systemapi
Additional information about your setup
This info above