How to Install an ATtiny Bootloader With Virtual USB
Contributors:
Shawn Hymel
Shawn Hymel 
Resources and Going Further
While this is a lot of information to take in, it shows how to hack the Arduino IDE to load custom board definitions. These steps should work for other ATtiny devices that are supported by the micronucleus project, such as:
You might have to modify the pins_arduino.h file, however, if you plan to use a different ATtiny.
ATtiny84 Pinout
If you need additional support, please check out the following resources.
If you want to go further with the ATtiny, please check out our additional tutorials that showcase the ATtiny:
Re-Programming the LilyTiny / LilyTwinkle
A quick tutorial showing how to reprogram the ATtiny85 IC found on the LilyTiny or LilyTwinkle boards.
Electronic E-craft Terrarium
A guest tutorial on an Electronic Terrarium from the Performative Sculpture class of Parsons DT.
Qwiic MP3 Trigger Hookup Guide
Playing MP3s has never been easier.
SparkFun Qwiic Dual Solid State Relay Hookup Guide
A Hookup Guide to get you started with the SparkFun Qwiic Dual Solid State Relay.