Problem while burning Bootloader ("verification error; content mismatch")

[system]

programmer
  baudrate = 9600;    # default is 115200   <--- add a slower baud rate here

Or, try uploading the bootloader file from the command line, eg.

 avrdude -c usbtiny -p m328p -U flash:w:optiboot_atmega328.hex -B9600

Now it works more often
Thanks!