Hi again. I just figured out the solution…
After re-flashing the bootloader successfully using the ESPRFTestTool, restart the ESP32C3 and enter the bootloader again (hold boot button, press reset button briefly, then release boot button). This will successfully connect to USB with a COM port in bootloader mode. Then go to your Arduino IDE and load a program (any) while hanging out in the bootloader. This will download your custom program. Then you can simply reset the device with the reset button and the program will run. Now when you power up by plugging the device into a USB port, it will be recognized as a COM port. They left this step out of the bootloader flashing instructions.
3 Likes