Firmware update issue: avrdude has no access to COM port  

RE: Firmware update issue: avrdude has no access to COM port

Just had the same Issue on Win 11, and for me the following steps solved it:

1. Open Device Manager
2. Expand the Menu on "Ports (COM & LPT)"
3. Double-click "Original Prusa i3 MKS (COM..)
4. Go to tab "Driver" and choose "Uninstall Device"
5. In the pop-up box make sure to check "Try to remove drivers" and click "ok"
6. In the menu of the Device Manager, click on "Acton", then choose "Scan for hardware changes", your Printer Driver will now be reinstalled new
7. Go back to Prusa Slicer and Flash your Firmware

Cheers

e.g. John

RE: Firmware update issue: avrdude has no access to COM port

great thanks, it helped! I changed the port from 3 to 20 and the firmware loaded correctly.

Thank a lot!!! SK-Jan

RE: Firmware update issue: avrdude has no access to COM port

Please help, I am unable to flash my printer's firmware.

I tried uninstalling the device from Device Manager and changing the COM-Port. (Win11 Pro)
I tried different USB cables and USB ports on my PC

I even tried once from a linux laptop with Prusa Slicer (installed from flathub if that matters).

All I get is this:

avrdude-slic3r -v -p atmega2560 -c wiring -P COM20 -b 115200 -D -U flash:w:0:E:\Install\Firmware\Prusa\MK3S_MK3S+_FW_3.14.0_MULTILANG.hex:i

avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Sep 18 2024 at 15:59:20
                Copyright (c) 2000-2005 Brian Dean,  http://www.bdmicro.com/ 
                Copyright (c) 2007-2014 Joerg Wunsch


                Using Port                    : COM20
                Using Programmer              : wiring
                Overriding Baud Rate          : 115200
avrdude-slic3r: stk500v2_recv(): timeout
avrdude-slic3r: stk500v2_getsync(): timeout communicating with programmer
avrdude-slic3r: Could not open port: COM20

avrdude-slic3r done.  Thank you.

RE: Firmware update issue: avrdude has no access to COM port

Update: I followed the steps described here: https://help.prusa3d.com/article/firmware-updating-issues-mk2-5s-mk3s-mmu2s-mmu3_2225 and checked the fuses. I did not perform the multimeter tests, as all other functions are working just fine.
I did a self test, which it passed.

When I connect my RPi with Octoprint via USB, I can connect and control the axis and temperatures.
The RPi Port is disabled.

According to the Troubleshooting Guide, all that's left is performing a factory reset. Which I would like to avoid if possible.

Oh, and it's a MK3S currently on version 3.13.2-7080. Didn't mention that in my first post.

RE: Firmware update issue: avrdude has no access to COM port

Turning off bluetooth solved the issue for me. Bluetooth was occupying the same port (COM3).