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:
The Uncertain 7-Cube
The Uncertain 7-Cube is a non-committal, less-than-helpful, but also entirely honest fortune teller. Simply ask it a yes or no question, give it a nudge, and the 7-Cube will dutifully inform you that it doesn’t have all the facts and doesn’t feel comfortable making a guess.
Installing a Bootloader on the MicroView
Fix your bootloader-less MicroView! This tutorial covers how to: disassemble the MicroView, wire it up to an assortment of programmers, program the bootloader, and test it out.
Electronic E-craft Terrarium
A guest tutorial on an Electronic Terrarium from the Performative Sculpture class of Parsons DT.
Qwiic Quad Relay Hookup Guide
SparkFun’s Qwiic Quad Relay is a product designed for switching not one but four high powered devices from your Arduino or other low powered microcontroller using I2C.