Can't update firmware - ser_send(): size/send mismatch
 
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gronk33
(@gronk33)
New Member
Can't update firmware - ser_send(): size/send mismatch

Hi there,

I'm on Windows 10. My MK2.5s is connected to my PC via USB on COM3 and I can see it listed in my device manager.

I've updated Prusa Slicr to 2.2. However whenever I try to flash the printer with 3.9.1 I get a host of errors (shown below).

I've never run into this issue before. I'm not running any other programs when I try to update.

Does anyone have any advice?

Thank you,

Ted

ERROR MESSAGE:

avrdude-slic3r -v -p atmega2560 -c wiring -P COM3 -b 115200 -D -U flash:w:0:C:\Users\tcp\Downloads\prusa3d_fw_3_9_1_MK25S\prusa3d_fw_MK25S_3_9_1_3518_RAMBo13a_en-de.hex:i

 

avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Mar 21 2020 at 12:45:57

                Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/

                Copyright (c) 2007-2014 Joerg Wunsch

 

 

                Using Port                    : COM3

                Using Programmer              : wiring

                Overriding Baud Rate          : 115200

avrdude-slic3r: ser_send(): size/send mismatch

avrdude-slic3r: stk500v2_send(): failed to send command to serial port

avrdude-slic3r: stk500v2_getsync(): can't communicate with device

avrdude-slic3r: Could not open port: COM3

 

avrdude-slic3r done.  Thank you.

Posted : 17/12/2020 10:01 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Can't update firmware - ser_send(): size/send mismatch
Posted by: @gronk33

Hi there,

I'm on Windows 10. My MK2.5s is connected to my PC via USB on COM3 and I can see it listed in my device manager.

I've updated Prusa Slicr to 2.2. However whenever I try to flash the printer with 3.9.1 I get a host of errors (shown below).

I've never run into this issue before. I'm not running any other programs when I try to update.

Does anyone have any advice?

Thank you,

Ted

ERROR MESSAGE:

avrdude-slic3r -v -p atmega2560 -c wiring -P COM3 -b 115200 -D -U flash:w:0:C:\Users\tcp\Downloads\prusa3d_fw_3_9_1_MK25S\prusa3d_fw_MK25S_3_9_1_3518_RAMBo13a_en-de.hex:i

 

avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Mar 21 2020 at 12:45:57

                Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/

                Copyright (c) 2007-2014 Joerg Wunsch

 

 

                Using Port                    : COM3

                Using Programmer              : wiring

                Overriding Baud Rate          : 115200

avrdude-slic3r: ser_send(): size/send mismatch

avrdude-slic3r: stk500v2_send(): failed to send command to serial port

avrdude-slic3r: stk500v2_getsync(): can't communicate with device

avrdude-slic3r: Could not open port: COM3

 

avrdude-slic3r done.  Thank you.

Hello and welcome to the Prusaforum!

Possibly something else is accessing the usb port. I would disable bluetooth or similar, maybe change the com port and start the slicer as admin.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 18/12/2020 3:04 pm
gronk33
(@gronk33)
New Member
Topic starter answered:
RE: Can't update firmware - ser_send(): size/send mismatch

@karl-herbert

Great advice - turning off bluetooth solved the problem. Thank you so much!

Posted : 19/12/2020 5:08 pm
FEST liked
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Can't update firmware - ser_send(): size/send mismatch

@gronk33

Thanks for the feedback! If only it was always that easy 👍 

happy printing!

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 19/12/2020 5:24 pm
FEST
 FEST
(@fest)
New Member
RE: Can't update firmware - ser_send(): size/send mismatch

@gronk33

Hello. I had the same issue here and fixed it by turning off bluetooth during the flash. This info should be added in the pdf doc with the firware update procecure I think...

Posted : 14/03/2021 6:40 pm
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