Possibility of installing custom firmware from Arduino Uno R3? I've been messing around with installing keyboard firmware onto my Arduino UNO R3 (I used this tutorial) and had an interesting idea: would it be possible to have this install custom firmware, automatically? If so, how would it be done via a DFU programmer?
Yes, if your Uno (or other Arduino) uses an Atmega8U2 or 16U2 for its USB interface, you can use dfu-programmer or dfutool within a script to automate downloading of new firmware into the USB interface chip(s).  In general, that new firmware should support USB communication with a host, plus whatever new capabilities you want to provide.