Cross Compiling Rust To openwrt `mipsel-unknown-linux-musl` on Mac OS Sequoia with UTM virtual machine

2026-07-17T00:00:00+00:00

At the time of this writting, rust support to mipsel-unknown-linux-gnu</code> has dropped to Tier 3</a> so using a linux VM is pretty much the best choice you have if you want to compile rust code for mips. Unless your OS is linux, and better yet, if you're running Debian, you can skip all the sections below regarding VM and use ansible to provision your own working environment.</p>

The sections 1 through 3 below are tried and true if you're working from Mac OS.</p>

1. Install UTM</h2>
Download and install UTM from https://mac.getutm.app</a></p>
2. Download Debian 13 (Trixie) image</h2>
Download debian image from https://cdimage.debian.org</a></p>
3. Create a new VM, set network mode to bridged</h2>
https://mac.getutm.app/</span></span></code></pre>

Note:</strong>
After creating the VM you must install Debian from the iso obtained on
step 2. The VM should have storage of at least 30GB, you might
consider defining a larger storage if you plan on building large mips
projects. But to build small rust projects to mips 30gb or 35gb should
suffice. At any rate you can always go back and create a new VM with
more storage especially because installing Debian on a VM takes
only approximately 5 minutes.</p>
</blockquote>
3.1. Creating the VM: network mode bridged</h3>
Make sure to enable network mode bridged so that your VM is visible
both within the host and out in your network. UTM defaults to shared network</code> which, in my experience, prevents the VM from accessing the
internet.</p>
4. Automate VM provisioning or download the QEMU image ready to go</h2>
I already prepared a QEMU image which you can download here</a>, by using this image you can skip the provisioning part.</p>
If you're a security freak like myself you probably feel uncomfortable
using such a pre-baked image and will run the
ansible</a> playbook below to
provision a new VM because the playbook code is pretty straightforward
and can be inspected both before and during the provisioning.</p>
4.1. Clone the ansible project</h3>
The project is in GitHub</a> and you can clone with:</p>
git</span> clone https://github.com/gabrielfalcao/rust-cross-compilation-qemu-vm-ansible.git</span></span></code></pre>4.2. Install UV</h3>
This is one of the few manual steps you must execute, in order to
install and run ansible in the project above you need to install UV</a></p>
4.3. Run the vm and configure the inventory</h3>
Log into the newly created VM and gather the IP address with the command below:</p>
ip</span> addr</span> |</span> grep</span> inet</span></span></code></pre>4.4. Edit hosts.yaml</h3>
Replace the ip address with the one obtained in step 4.3.</p>
all</span>:</span></span>
  hosts</span>:</span></span>
    vm</span>:</span></span>
      ansible_host</span>:</span> 192.168.8.222</span> # REPLACE THIS UP ADDR</span></span>
      ansible_user</span>:</span> debian</span></span>
      ansible_password</span>:</span> ok</span></span>
</span>
</span>
      ## optional, use your own ssh key below, or comment</span></span>
      ## the code.</span></span>
      ##</span></span>
      ## Ansible will use username/password authentication</span></span>
      ## which appears to be the only choice in a fresh Debian</span></span>
      ## installation.</span></span>
</span>
      ansible_ssh_private_key_file</span>:</span> ~/.ssh/id_ed25519</span></span>
      ##</span></span></code></pre>4.5. Provision the machine</h3>
Run the command below from the directory where you cloned the repo.</p>
make deploy</span></span></code></pre>

NOTE</strong>
The Makefile</code> already summons uv to create a new virtual python
environment, install ansible and run the provisioning. It's all pretty
straightforward make code which you should be able to inspect effortlessly.</p>
</blockquote>
5. Compile rust code to mips</h3>
You can test if everything worked by accessing the VM via SSH. Create
a new rust project and run the build with the commands below:</p>
cargo</span> new test-crossbuild</span></span>
cargo</span> cross build</span> --target=mipsel-unknown-linux-musl</span></span></code></pre>6. Heavy lifting done</h3>
Depending on the complexity of the project, you might need to tweak
RUSTFLAGS.  I might write follow-up blog posts covering such minutiae
tweaks, but the steps in this tutorial and the ansible provisioning
already cover all the heavy lifting of having an environment to work
with.</p>
6.1. Where to tweak</h4>
The ansible provisioning installs rust at /opt/rust, so
CARGO_HOME</code></strong> is /opt/rust/cargo</code>, RUSTUP_HOME</code></strong> is
/opt/rust/rustup</code>.</p>
Environment variables are set in two places:</p>

/etc/environment</code></li>
/etc/bash.bashrc</code></li>
</ul>
Cargo config is at: /opt/rust/cargo/config.toml</code></p>
Enjoy</h3>
I've spend enough time trying to get the details write for the kind of
embedded Rust work I've been doing in my free time and wish I had
found an automated solution like the one in this blog post. So I hope
I am helping people save their time.</p>
Cheers, and Happy Hacking!</p>

4.2. Install UV</h3>
This is one of the few manual steps you must execute, in order to install and run ansible in the project above you need to install UV</a></p>

`Enjoy</h3> I've spend enough time trying to get the details write for the kind of embedded Rust work I've been doing in my free time and wish I had found an automated solution like the one in this blog post. So I hope I am helping people save their time.</p> Cheers, and Happy Hacking!</p>`

Cross Compiling Rust To openwrt `mipsel-unknown-linux-musl` on Mac OS Sequoia with UTM virtual machine

2. Download Debian 13 (Trixie) image</h2>
Download debian image from https://cdimage.debian.org</a></p>

You should Switch From jq to jaq

Cross Compiling Rust To openwrt `mipsel-unknown-linux-musl` on Mac OS Sequoia with UTM virtual machine

2. Download Debian 13 (Trixie) image</h2> Download debian image from https://cdimage.debian.org</a></p>

4.2. Install UV</h3> This is one of the few manual steps you must execute, in order to install and run ansible in the project above you need to install UV</a></p>

Enjoy</h3> I've spend enough time trying to get the details write for the kind of embedded Rust work I've been doing in my free time and wish I had found an automated solution like the one in this blog post. So I hope I am helping people save their time.</p> Cheers, and Happy Hacking!</p>

You should Switch From jq to jaq

2. Download Debian 13 (Trixie) image</h2>
Download debian image from https://cdimage.debian.org</a></p>

4.2. Install UV</h3>
This is one of the few manual steps you must execute, in order to install and run ansible in the project above you need to install UV</a></p>

`Enjoy</h3> I've spend enough time trying to get the details write for the kind of embedded Rust work I've been doing in my free time and wish I had found an automated solution like the one in this blog post. So I hope I am helping people save their time.</p> Cheers, and Happy Hacking!</p>`