arduino-cli-go-native

Install arduino-cli on Apple Silicon Macs without any dependency on Rosetta 2 — no Arduino IDE required, just the CLI native.

The problem this solves

arduino-cli itself ships native arm64 builds, and Homebrew's avr-gcc, avrdude, and arm-none-eabi-gcc are all natively compiled for Apple Silicon too. So it would be reasonable to assume a brew install arduino-cli plus arduino-cli core install arduino:avr gets you a fully native toolchain. It doesn't.

Arduino's own board-manager packages — the avr-gcc, avrdude, and arm-none-eabi-gcc builds that arduino-cli core install downloads into ~/Library/Arduino15/packages/ — are still published for macOS as x86_64-only. The official package index even says so explicitly: Apple Silicon Macs are simply pointed at the Intel build, to be run under Rosetta. This is a known, long-open issue (arduino/toolchain-avr#91) with no sign of a native build arriving any time soon.

Since Apple has announced Rosetta 2 is headed for deprecation, that's not a future reasonable people may want to depend on.

What this script does

1. Installs native arm64 builds of avr-gcc (via the osx-cross/avr tap), avrdude, arm-none-eabi-gcc, bossa, and arduino-cli through Homebrew, and verifies each one is actually arm64 (not just installed).
2. Wipes any existing ~/Library/Arduino15 state and does a clean arduino-cli core install of the platforms avr, sam, and samd. This step still downloads Arduino's x86_64 toolchain packages — that's unavoidable, since arduino-cli always fetches a platform's declared tool dependencies.
3. Walks every binary Arduino actually downloaded and symlinks it to the matching native Homebrew binary in place, so the same file paths that platform.txt expects now resolve to native arm64 code.

The result: arduino-cli compile / upload never touches an x86_64 binary, and never needs Rosetta, for the boards below. Others should be easy to add.

Boards covered

Board(s)	Arduino core	Toolchain
Uno, Leonardo, Pro/Pro Mini, Mini, Mega, Nano	arduino:avr	avr-gcc, avrdude
Due	arduino:sam	arm-none-eabi-gcc, bossac
MKR Zero	arduino:samd	arm-none-eabi-gcc, bossac

Side note

Each downloaded package does still carry some genuinely-unused x86_64 content afterward: GCC's internal single-purpose binaries (cc1, cc1plus, collect2 and similar) live in a nested directory outside bin/, so the by-name swap never touches them. That's harmless — once the top-level tool is the native Homebrew one, it calls its own internal helpers from inside its own Homebrew keg, never the Arduino package's.

Requirements

• Apple Silicon Mac
• Xcode Command Line Tools
• native* Homebrew install at /opt/homebrew (not /usr/local, and not a Terminal session running under Rosetta — check with arch, should print arm64)

Usage

./arduino-cli-go-native

Flags:

Flag	Effect
-h, --help	Show usage info
-V, --Version	Show script version
--coreUpgrade	Skip the brew installs and core install steps; only re-run the symlink swap. Use this after you've manually run arduino-cli core upgrade, which can pull in a new toolchain version (and therefore a fresh set of x86_64 binaries) under a new version-numbered folder. This has not been tested yet

Verify it worked:

arduino-cli compile --fqbn arduino:avr:uno --verbose /path/to/sketch

The invoked compiler path in the verbose output should resolve into your Homebrew prefix, not into an Arduino15 tools path.

A gotcha worth knowing about

If you hit compiler errors that look like macOS SDK header conflicts (e.g. error: architecture not supported coming from deep inside /Library/Developer/CommandLineTools/SDKs/...) even after this script reports everything as arm64 — that's very likely a different problem: a CPATH or CPLUS_INCLUDE_PATH environment variable set globally in your shell profile (often left over from getting some other GNU/Homebrew package building on macOS) leaking the host macOS SDK into the cross-compiler's header search path. Check with:

env | grep -i -E "cpath|include"

and scope any hits to the specific build that needs them rather than your whole shell profile. Cross compilers need clean include path environment variables.

License

MIT — use, modify, and redistribute freely.