This guide was written for MacOS Monterey (12.2.1) running on Apple silicon (M1, M1 Pro, M1 Max). These steps may also work on older MacOS and OSX versions. These instructions are provided for your convenience and education ONLY. No warranty or technical support is implied by your use of these instructions, firmware, or third-party software mentioned in this article.
Download the TH3D Bootloader Package, which is in ZIP format. Once saved to your Mac, double-click to unzip the files. You should have folders and files as seen here:
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Folders once the bootloader package is unzipped
Go to the "MacOSX Arduino" folder and unzip BOTH the "arduino-1.8.12-macosx.zip" and "TH3DArduinoLibraries.zip" files. The first file will create an Arduino.App, and the second will create a "hardware" folder as seen here:
After the two ZIP files are unzipped, you should have the contents seen here.
Double-click the Arduino.app file to launch ArduinoIDE for the first time. When you do, this creates a folder in your main Documents folder. Inside the Arduino folder is another called "libraries". Keep this location in mind, we'll be right back!
In the bootloader package, you unzipped the "TH3DArduinoLibraries" file, and that created a folder called "hardware". Copy the "hardware" folder into your Documents > Arduino file. When complete, you should have both a "libraries" and a "hardware" folder there:
Copy the "hardware" folder from the bootloader package to Documents > Arduino. You should have a "libraries" and a "hardware" folder here now.
After the folder is copied, go back into the bootloader package and double-click the Arduino.app to launch ArduinoIDE again.
To verify that Arduino found the hardware folder, look under the Tools > Board menu and make sure you have options for the "Arduino Uno", "Arduino Mega 2560", and "Sanguino 1284p" as seen here:
When the hardware libraries are copied to the correct place, Arduino now shows options for 1284p and 2560 processors as seen here.
Now that the ArduinoIDE software has been prepared, follow the steps in our generalized bootloader guide.