How to avoid installing Rosetta on an Apple Silicon Mac

Development Tools IDE 2.x
1

To get the Arduino IDE working on Apple Silicon, you have to provide a replacement compiler and uploader built for Apple Silicon, and then create a local configuration file that tells the Arduino IDE to use those updated versions.

I started by following the instructions here: Apple Silicon functional toolchain

The gist of this is to replace avr-gcc, ctags, and avrdude with apple silicon native versions, then to point the IDE preferences file to use the correct versions.

Step 1: Install avr-gcc

  1. Install Xcode Command Line Tools
    Before installing avr-gcc, make sure you have Xcode command line tools installed. Open your Terminal and run:

    xcode-select --install

  2. Install avr-gcc via Homebrew
    If you haven’t installed Homebrew yet, follow the instructions on brew.sh. Once it's set up, run the following commands to install avr-gcc:

    brew tap osx-cross/avr
brew install avr-gcc

    At the time of this writing, avr-gcc version 9.4.0_1 is the latest. You can find the installed files under:

    /opt/homebrew/Cellar/avr-gcc@9/9.4.0_1/bin/

  3. Copy avr-gcc to Arduino Library
    To integrate the new compiler with Arduino, copy the entire version folder into the Arduino package directory:

    cp -r /opt/homebrew/Cellar/avr-gcc@9/9.4.0_1/ ~/Library/Arduino15/packages/arduino/tools/avr-gcc/

Step 2: Install ctags

  1. Clone the ctags Repository
    If you don’t have the GitHub CLI installed, you can install it with:

    brew install gh

    Then, clone the ctags repository:

    gh repo clone arduino/ctags

  2. Edit the Source Code
    Navigate to the cloned folder and edit the general.h file to fix a bug. Find the line:

    # define __unused__  __attribute__((unused))

    And replace it with:

    //# define __unused__  __attribute__((unused))
# define __unused__

  3. Build and Install ctags
    Next, configure and make the build:

    cd ctags  # Navigate to the cloned ctags directory
./configure
make

    Before replacing the existing ctags, back it up first:

    mv ~/Library/Arduino15/packages/builtin/tools/ctags/5.8-arduino11/ctags ~/Library/Arduino15/packages/builtin/tools/ctags/5.8-arduino11/ctags.bak

    Then, copy the newly built ctags to the Arduino package directory:

    cp ctags ~/Library/Arduino15/packages/builtin/tools/ctags/5.8-arduino11/

Step 3: Install avrdude

  1. Install avrdude Using Homebrew
    Just like before, install avrdude using:

    brew install avrdude

    After installation, copy the entire avrdude folder into the Arduino tools directory:

    cp -r /opt/homebrew/Cellar/avrdude/8.0 ~/Library/Arduino15/packages/arduino/tools/avrdude

  2. Locate and Copy the avrdude.conf File
    The necessary configuration file may be located at:

    /opt/homebrew/etc/avrdude.conf

    Create a directory for the configuration file within the Arduino tools structure:

    mkdir ~/Library/Arduino15/packages/arduino/tools/avrdude/8.0/etc
cp /opt/homebrew/etc/avrdude.conf ~/Library/Arduino15/packages/arduino/tools/avrdude/8.0/etc/avrdude.conf

Step 4: Update Arduino IDE Configuration

  1. Quit Arduino IDE
    Make sure to exit the Arduino IDE completely.

  2. Edit platform.local.txt
    Open your favorite text editor and create a new file. Add the following lines to configure the IDE to use the new tools:

    compiler.path={runtime.tools.avr-gcc-9.4.0_1.path}/bin/
tools.avrdude.cmd.path={runtime.tools.avrdude-8.0.path}/bin/avrdude
tools.avrdude.config.path={runtime.tools.avrdude-8.0.path}/etc/avrdude.conf

    Make sure to save the file to:

    ~/Library/Arduino15/packages/arduino/hardware/avr/1.8.6/platform.local.txt

    (Remember, the Library folder is hidden by default; press Command + Shift + . to make it visible.)

Final Step: Restart the Arduino IDE