Make your Uno Kit USB serial firmware missing ?

Please add the firmware for the ATmega16U2 on the [**Make Your UNO Kit**](https://docs.arduino.cc/hardware/make-your-uno-kit/)'s USB to serial bridge module.

After flashing my with [the firmware hex file for the UNO R3's bridge](https://github.com/arduino/ArduinoCore-avr/blob/29d637e0ae724eeaebfd8fcd321903369b8d7b5a/firmwares/atmegaxxu2/Arduino-COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex), I am unable to upload to my "Make Your UNO" board.

I believe the UNO R3 hex file is not suitable for use with the bridge module on the **Make Your UNO Kit**.

### Additional context

The upload still fails even after replacing the ATmega328P on my "Make Your UNO" board with one from a working Arduino Uno. This result supports my hypothesis that the problem truly is with the bridge firmware.

#### Additional reports

- https://forum.arduino.cc/t/atmel-16u2-issue-with-uploading-sketch-arduino-uno-make-your-uno-kit/1431819

Start with the existing firmwares/atmegaxxu2/Arduino-COMBINED-dfu-usbserial-atmega16u2-Uno-Rev3.hex and the Make Your UNO Kit hardware documentation linked in the issue. Compare the bridge hardware requirements and firmware behavior, then verify that the resulting firmware permits uploads to the Make Your UNO board.

Written by the indexing model from the issue text.