avrdude: Error: butterfly programmer uses avr_write_page() but does not provide a cmd() method When trying to flash my sketch, I see many errors such as:

 ***failed;                                                                                                                            
 ***failed;                                                                                                                            
 ***failed;                                                                                                                            
avrdude: Error: butterfly programmer uses avr_write_page() but does not                                                                
provide a cmd() method.                                                                                                                                                                                           
 *** page 127 (addresses 0x7400 - 0x747f) failed to write


And also:

avrdude: error: programmer did not respond to command: set addr


How can I successfully flash my sketch?
After much frustration in trying things, I came across this forum post which advised:

sudo systemctl stop ModemManager.service


If this works, disable the service from starting next boot:

sudo systemctl disable ModemManager.service


It seems like setting ENV{ID_MM_DEVICE_IGNORE}="1" in a udev rule is insufficient.