Some Signs a bootloader might be corrupt, or incorrect:
- FC does not appear as Arduino Leonardo under a com port.
- FC appears in device manager but with a yellow exclamation point.
- When plugging in the FC you are warned about a missing device descriptor.
- Computer doesn’t detect the FC at all.
How to Flash a Bootloader using a USBasp
This process assumes Arduino Software is installed, you have a soldering iron, header pins, and a USBasp along with a Micro JST 1.0mm 6 pin connector – Sparkfun or eBay for the classic or a Micro JST 1.5mm 6 pin connector – eBay for the narrow. For Windows, you may also need the USBasp drivers.
1.) Connect/solder the wires from the Micro JST 1.0 6 pin connector to the SPI, matching the pinout as shown.
2.) Plug the USBasp into your computer
4.) Navigate to Tools > Programmer, and select USBasp
5.) Navigate to Tools again, and select Burn Bootloader
You’ll be presented with a message at the bottom of the Arduino window stating “Burning Bootloader to I/O Board (this may take a minute)“. During this time notice that both data LEDS on the USBasp are solid.
Once Arduino is finished, there should be a message stating “Done Burning Bootloader“.
6.) At this point your board should have a compatible bootloader, and you can proceed to Install a Sketch.