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Build mavlink-router as Static AArch64 musl Binary

mavlink-router forwards MAVLink packets between UART, UDP, and TCP endpoints. It is useful on a companion computer or embedded Linux board when one MAVLink source should be shared by several clients.

This guide builds mavlink-routerd as a static AArch64 Linux binary using the musl cross compiler from musl.cc.

Read more on linux toolchain and cross compiler linux cross compiler toolchain

Step 1: install host tools

Install the tools used to download and build the source:

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sudo apt update
sudo apt install git meson ninja-build pkg-config file wget
  • git: download mavlink-router.
  • meson: configure the build.
  • ninja: run the build.
  • pkg-config: helper used by many C/C++ build systems.
  • file: check the output binary type.
  • wget: download the musl cross compiler archive.

Step 2: install aarch64 musl cross compiler

Download the prebuilt musl.cc toolchain:

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cd /tmp
wget https://musl.cc/aarch64-linux-musl-cross.tgz
tar -xf aarch64-linux-musl-cross.tgz
sudo mv aarch64-linux-musl-cross /opt/

Tip

The archive name is selected by the target CPU, not by the host CPU.

For an x86_64 Ubuntu host that builds for aarch64 Linux, use:

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aarch64-linux-musl-cross.tgz

Add the compiler to your shell path:

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echo 'export PATH=/opt/aarch64-linux-musl-cross/bin:$PATH' >> ~/.bashrc
source ~/.bashrc

Step 3: verify the compiler

Check that the C and C++ compilers are available:

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/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-gcc --version
/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-g++ --version

These tools run on the host machine and create AArch64 Linux binaries linked against musl.

From your workspace root:

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mkdir -p external
git clone --depth 1 https://github.com/mavlink-router/mavlink-router.git external/mavlink-router
git -C external/mavlink-router submodule update --init --recursive --depth 1

The submodule step is required because mavlink-router uses the MAVLink C library as a dependency.

Step 5: record the source revision

Record the exact source version used for the build:

git -C <path> ... means: run the Git command as if you first changed directory to .

Example:

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git -C <path> status

is equivalent to:

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cd <path>
git status

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git -C external/mavlink-router rev-parse HEAD
git -C external/mavlink-router submodule status

This makes the build easier to reproduce later.

Step 6: create the Meson cross file

Create the toolchain folder:

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mkdir -p toolchains

Create toolchains/aarch64-linux-musl.ini:

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[binaries]
c = '/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-gcc'
cpp = '/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-g++'
ar = '/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-ar'
strip = '/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-strip'

[host_machine]
system = 'linux'
cpu_family = 'aarch64'
cpu = 'aarch64'
endian = 'little'

[built-in options]
c_args = ['-Os']
cpp_args = ['-Os']
c_link_args = ['-static', '-no-pie']
cpp_link_args = ['-static', '-no-pie']
default_library = 'static'
b_lto = true
b_pie = false

Important static build settings:

  • default_library = 'static': prefer static libraries.
  • c_link_args = ['-static', '-no-pie']: statically link C code.
  • cpp_link_args = ['-static', '-no-pie']: statically link C++ code.
  • b_pie = false: avoid position-independent executable mode for this static build.

Step 7: configure with Meson

Remove any old build folder:

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rm -rf build/mavlink-router-aarch64-musl-static

Configure the cross build:

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meson setup \
  build/mavlink-router-aarch64-musl-static \
  external/mavlink-router \
  --cross-file toolchains/aarch64-linux-musl.ini \
  --buildtype release \
  --strip \
  -Dsystemdsystemunitdir=/usr/lib/systemd/system

What this command does:

  • build/mavlink-router-aarch64-musl-static: output build directory.
  • external/mavlink-router: source directory.
  • --cross-file: tells Meson which compiler and target machine to use.
  • --buildtype release: optimized release build.
  • --strip: strip symbols during install/build output where supported.
  • -Dsystemdsystemunitdir=...: sets the systemd unit install path.

Step 8: build with Ninja

Build the project:

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ninja -C build/mavlink-router-aarch64-musl-static

The main binary is:

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build/mavlink-router-aarch64-musl-static/src/mavlink-routerd

Strip the final binary:

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/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-strip \
  build/mavlink-router-aarch64-musl-static/src/mavlink-routerd

Step 9: verify the binary

Check that the output is an aarch64 executable:

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file build/mavlink-router-aarch64-musl-static/src/mavlink-routerd

Expected output should include:

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ELF 64-bit LSB executable, ARM aarch64, statically linked

Check the ELF header:

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/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-readelf \
  -h build/mavlink-router-aarch64-musl-static/src/mavlink-routerd

Check that there is no dynamic interpreter:

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/opt/aarch64-linux-musl-cross/bin/aarch64-linux-musl-readelf \
  -l build/mavlink-router-aarch64-musl-static/src/mavlink-routerd | grep INTERP || echo "no dynamic interpreter"

Expected interpreter check:

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no dynamic interpreter

Step 10: test with QEMU

Install QEMU user emulation:

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sudo apt install qemu-user

Run the help command:

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QEMU_AARCH64="$(command -v qemu-aarch64-static || command -v qemu-aarch64)"
"$QEMU_AARCH64" build/mavlink-router-aarch64-musl-static/src/mavlink-routerd -h

The command should print the mavlink-routerd usage text.

Step 11: copy to Raspberry Pi

Copy the static binary to a Raspberry Pi target:

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scp build/mavlink-router-aarch64-musl-static/src/mavlink-routerd pi5:/tmp/mavlink-routerd

Check it on the Raspberry Pi:

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ssh pi5 'chmod +x /tmp/mavlink-routerd && file /tmp/mavlink-routerd && /tmp/mavlink-routerd -h | head -40'

If file is not installed on the Raspberry Pi, run only:

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ssh pi5 'chmod +x /tmp/mavlink-routerd && /tmp/mavlink-routerd -h | head -40'

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