USB 2.0 ports not working on the Compute Module 4? Check your overlays!

Out of the box, to conserve power, the new Raspberry Pi Compute Module 4 doesn't enable its built-in USB 2.0 ports.

Compute Module 4 IO Board USB 2.0 ports are disabled by default

You might notice that if you plug something into one of the USB 2 ports on the IO Board and don't see it using lsusb -t. In fact, you see nothing, by default, if you run lsusb -t.

To enable the USB 2.0 ports on the Compute Module 4, you need to edit the boot config file (/boot/config.txt) and add:


Then reboot the Pi. Now you should be able to use the built-in USB 2.0 ports!

Kubernetes 101 livestream series starts Nov 18th!

On November 18th, at 11 a.m., the first episode of my upcoming Kubernetes 101 livestream series will start on my YouTube channel.

Kubernetes 101 Series Artwork

The first episode will be available here on YouTube: Kubernetes 101 - Episode 1 - Hello, Kubernetes!.

You can find more details about the series on my Kubernetes 101 site, and there is also an open-source Kubernetes 101 GitHub repository which will contain all the code examples for the series.

In the spring, I presented a similar livestream series, Ansible 101, covering all the basics of Ansible and setting people up for success in infrastructure automation.

Travis CI's new pricing plan threw a wrench in my open source works

I just spent the past 6 hours migrating some of my open source projects from Travis CI to GitHub Actions, and I thought I'd pause for a bit (12 hours into this project, probably 15-20 more to go) to jot down a few thoughts.

I am not one to look a gift horse in the mouth. For almost a decade, Travis CI made it possible for me to build—and maintain, for years—hundreds of open source projects.

I have built projects for Raspberry Pi, PHP, Python, Drupal, Ansible, Kubernetes, macOS, iOS, Android, Docker, Arduino, and more. And almost every single project I built got immediate integration with Travis CI.

Without that testing, and the ability to run tests on a schedule, I would have abandoned most of these projects. But with the testing, I'm able to keep up with build failures induced by bit rot over the years and review PRs more easily.

What went wrong with Travis CI?

From the outset, Travis CI was built to integrate with GitHub repositories and offer free open source CI. At one time it was showered with praise on Hacker News and elsewhere for its culture and ethos.

Cross-compiling the Raspberry Pi OS Linux kernel on macOS

After doing a video testing different external GPUs on a Raspberry Pi last week, I realized two things:

  1. Compiling the Linux kernel on a Raspberry Pi is slow. It took 54 minutes, and I ended up doing it 7 times during the course of testing for that video.
  2. If you ever want to figure out a better way to do something, write a blog post or create a video showing the less optimal way of doing it.

To the second point, about every fifth comment was telling me to cross-compile Linux on a faster machine instead of doing it on the Pi itself. For example:

cross compile raspberry pi kernel youtube comment

And on the Pi Forums, it seems like nobody worth their salt compiles the kernel on the Pi either, so I figured—since I'm probably going to have to do it again another thousand times in my life—I might as well put together a guide for how to do it on a Mac.

How to flash Raspberry Pi OS onto the Compute Module 4 eMMC with usbboot

The Raspberry Pi Compute Module 4 comes in two main flavors: one with built-in eMMC storage, and one without it. If you opt for a Compute Module 4 with built-in eMMC storage, and you want to write a new OS image to the Compute Module, or manually edit files on the boot volume, you can do that just the same as you would a microSD card—but you need to first make the eMMC storage mountable on another computer.

This blog post shows how to mount the eMMC storage on another computer (in my case a Mac, but the process is very similar on Linux), and then how to flash a new OS image to it.

Video Instructions

In addition to the tutorial below, I published a video version of this post covering installation and usage of rpiboot for flashing the eMMC on Windows, Ubuntu, Raspberry Pi OS, or macOS:

The Raspberry Pi 400 can be overclocked to 2.2 GHz

After the Raspberry Pi 400 was launched earlier this morning, there was a lot of discussion over the thermals and performance of the upgraded 1.8 GHz System on a Chip inside:

Pi 4 model B and Pi 400 BCM2711 SoC Broadcom chip number difference

I wanted to spend a little time in this post testing overclocking, performance, power consumption, and thermals in depth.

Video version

There is also a video that goes along with this post, if you're more visually-inclined: