[Ducky firmware that can emulate a USB-Serial adapter]

I don't see why emulating a HID and mass storage is any different than emulating a HID and serial adapter...

[Ducky firmware that can emulate a USB-Serial adapter]

I did a cursory search but could not find anything like this. Basically, I want to be able to drop a small payload through the keyboard that opens the serial port so that it can be used to stream a lot of binary data faster than it could be sent over the keyboard interface. Is anyone aware of a ducky firmware that is able to emulate both a keyboard and a serial port? Bidirectional communication is not a requirement but it would be nice to have.