Re-Programming the LilyTiny / LilyTwinkle
ATTiny Board Add-On Files
Before we start, we need to setup the Arduino programming environment to handle the ATTiny hardware. The ATTiny is not part of the "default" board files that comes with Arduino IDE v1.x. You will need to "install" these board files to your Arduino environment in order to re-program your LilyTiny.
Manually Installing the ATtiny hardware files
If you prefer to manually install the files, we will first need to install the ATtiny hardware board files. Download the zipped files from the GitHub repository to manually install the files.
Create a folder under your Arduino sketchbook called "hardware."
Locate your Arduino sketchbook folder (you can find its location in the preferences dialog in the Arduino software) - this is typically under Documents > Arduino
Create a new sub-folder called “hardware” in the sketchbook folder, if it doesn’t exist already.
Open (unzip) the attiny-master.zip file and copy the “attiny” folder (not the attiny-master folder) from the unzipped attiny-master.zip file to your new “hardware” folder.
You should end up with folder structure like Documents > Arduino > hardware > attiny that contains the boards.txt file and another folder called variants.h.
Restart the Arduino IDE.
You should see ATtiny entries in the Tools > Board menu.