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32U4 codes run only when connected to a pc


My balboa works fine as long as the usb is plugged into the system. However, on disconnecting the usb, none of the programs run. I am suspecting a bootloader issue. I have been attempting to reflash the bootloader and got the error:

makefile:153: …/…/…/…/…/…/LUFA/LUFA-111009/LUFA/makefile: No such file or directory .

The LUFA url in caterina-A-Star.txt doesn’t seem to be available.

Any suggestions?

Thank You and Regards,


Before getting into reflashing the bootloader, it would be good to do a few basic tests to make sure that the robot is getting powered from the batteries as expected. Did it ever work for you when powered separately from USB? When you press the power button (with the USB disconnected), do you see the blue LED near the USB connector light up? You should also check to make sure your batteries are freshly charged. Can you measure the voltage at the VBAT and VSW pin? The VBAT pin is located near the Pololu logo and VSW can be found near the USB connector.

Also, could you post close-up pictures of your Balboa Robot, preferably with some that clearly show the soldering on your battery contacts?



The robot works fine when powered from only usb or powered from batteries and connected to the usb. The batteries are freshly charged. The VSW voltage is 4.5 V. VBAT is 6.9 V.


Did it ever work for you when powered from the batteries, separately from USB?

VSW should be approximately the same voltage as VBAT when the robot is powered on, so if it is reading 4.5V, there is a problem somewhere. 6.9V is a little low for freshly charged batteries; do you have another set you can try with and see if that helps by measuring VBAT and VSW again?

It is difficult to see the solder on your battery terminals, but they look like they might not be properly wetted, which could cause an intermittent connection, so if that is the case, you might try reflowing them to make sure. If that does not help, could you post some more pictures of the PCB side of the robot that clearly show the whole control board?


Hi Brandon,

The robot was working fine before. The issue started a few times after using the usb port for serial communication with raspberry pi zero w. I was able to use the robot a few times in this setup before.


Thank you for the additional information. Can you try the suggestions I made previously and post the updated pictures as well?

Also, could you post the code that is currently loaded onto your Balboa robot?