by Sutajio Kosagi

Mobile, Open Hardware, RISC-V System-on-Chip (SoC) Development Kit

Dec 03, 2021

Production Start, Livestream, and Giveaway!

Just a quick update from the line in Korea - we've started production of the Precursor PCBAs! Here are some photos of the journey thus far. And, before I forget: you can catch me (bunnie) and xobs on a Crowd Supply Teardown Sessions livestream happening on Thursday, December 16, 2021 at 9 PM Pacific. Even better, Crowd Supply is giving away a Precursor. See you there! Read the full update.

Oct 27, 2021

Xous: Bug Scrub, Stupid Network Tricks; Production Update; and Boycott the UKCA!

We're picking up speed! Keep reading for the latest on Xous development, hardware production, and certification. Read the full update.

Aug 25, 2021

Xous 0.9 Release, Secured Boot, EMC Testing Redux, And the Road to Production

What a busy summer it has been! We’re overdue for a comprehensive update. So, without further ado, here’s the latest news on Precursor. Read the full update.

Aug 04, 2021

Adding Rust-Stable libstd Support for Xous

It is possible to add support for a new OS to the Rust compiler's stable channel without rebuilding everything, enabling libstd support for entirely new operating systems. Read the full update.

Jun 02, 2021

Supply Chain, Xous, EMC, and Keyboard Updates

Here's the latest from the Precursor team, including an update on supply chain issues, keyboard samples, and more. Plus an in-depth look at how we implemented "Suspend/Resume" functionality. Read the full update.

Apr 20, 2021

Software, Pre-Boot, Testing, Certification, and Time Lines

This update covers the release of Xous 0.8, the Precursor pre-boot process, the design of our test jigs, our preparations for EMC testing, and our various attempts to accelerate the manufacturing process. Read the full update.

Mar 15, 2021

From Steel to Supply Chains to Operating Systems to...Bitcoin???

It’s been a couple months since our last update, in part because the world has been in rapid flux and it’s been a struggle to establish ground truth on a number of production-critical factors. The last time we wrote, the very first doses of the Pfizer vaccine were being administered, while the US Capitol was under assault. Now, about 20% of the US has received at least one dose of a vaccine, and a massive stimulus package is being signed into law. This update covers supply-chain delays, omakase case candidates, Precursor sales in Bitcoin, and a status report on the Xous operating system. Read the full update.

Jan 07, 2021

Kicking off Manufacturing in a New Year

Manufacturing and certification during the Lunar New Year... read all about the challenges of development during a major holiday and a pandemic. Read the full update.

Dec 16, 2020

Wow. Thank You, Precursor Community!

When we launched this campaign, we knew we were going into some serious headwinds. 2020 has been a rough year for all of us, and we were up against a very busy news cycle. When I woke up this morning, I saw that the campaign had closed at $398,661. I had to rub my eyes and hit refresh a couple times to make sure I wasn't dreaming: this was beyond my highest expectations. Thank you! Read the full update.

Dec 15, 2020

The Last Day of Our Campaign!

We're down to the last day of the campaign! We've cleared our funding target with a few days to spare, and momentum has been steadily building toward the stretch goal of $280k that will bring all devices a battery upgrade! And remember, today is your last day to enjoy our discounted crowdfunding price or to pick up a Limited Edition Precursor! Read the full update.

Dec 10, 2020

Stretch Goal: Larger Battery!

We've done the math, and if we can hit $280,000, we can afford to upgrade our 1100 mAh battery to a full-custom, 1300 mAh model. So help us spread the word, and let's see if we can give every Precursor an extra hour of battery life (and an extra 12 hours of standby)! Read the full update.

Dec 09, 2020

What’s the Value of Hackable Hardware, Anyway?

There is plenty of skepticism around the value of hackable products. Significantly, hackability is different from openness: cars are closed-source, yet support vibrant modding communities; gcc is one of the “real OG”s of open source, but few users find it easy to extend or enhance. Is it better to have a garden planted by the most knowledgeable botanists and maintained by experienced gardeners, or an open plot of land maintained by whoever has the interest and time? In this update, we explore these issues in the context of Precursor. Read the full update.

Dec 03, 2020

Our Mechanical Design

“Pocketability” is the difference between Precursor and naked PCB FPGA development platforms. We hope Precursor’s pocketability helps bring more open hardware out of the lab and into everyday use. Thus, the mechanical design of Precursor is of similar importance to its electrical, software, and security design. Read the full update.

Nov 25, 2020

How We Make Our Custom PCBs

In this post, we take a step-by-step look at the manufacturing process of Precursor's circuit board. If you're curious about the details of modern PCB manufacturing, this post is a great introduction. Read the full update.

Nov 23, 2020

AMA: Your Chance to Ask All the Questions!

Bunnie and xobs are hosting an AMA on Crowd Supply's Discord channel at 9 AM Pacific Time, this coming Wednesday, Nov 25th. Come join us! Read the full update.

Nov 19, 2020

Evaluating Our Hardware Security

This post is an in-depth look at the issues of hardware security and how Precursor works to mitigate them. Read the full update.

Nov 12, 2020

Software Development for Precursor

Here's a post, including code samples, from xobs explaining how he developed the software for Precursor with Renode and C#. Read the full update.

Nov 05, 2020

A Guided Tour of the Precursor System on Chip (SoC)

This post provides a whirlwind tour through Precursor's System on Chip. Read the full update.

Nov 01, 2020

Crowdfunding Begins!

We are happy to announce that the Precursor campaign is live. Please check out our crowdfunding page to learn more. In the coming months, we'll be posting lots of detailed information about Precursor. We'll also be hosting an AMA on Crowd Supply's Discord channel, so stay tuned! Read the full update.

Sep 24, 2020

A Guided Tour of the Precursor Motherboard

This post provides a guided tour of the components and features of the Precursor motherboard. Read the full update.

Sep 18, 2020

The Platform

Precursor is a mobile, open source electronics platform. Similar to how a Raspberry Pi or an Arduino can be transformed into an IoT gadget with the addition of a couple breakout boards, some solder, and a bit of code, Precursor is a framework upon which you can assemble a wide variety of DIY mobile applications. This update talks a bit about what makes Precursor unique, and then moves on to the ins and outs of our design philosophy. Read the full update.

Sep 10, 2020


Why do we trust our computers? I’ve done a lot of thinking on this question. The answer, it turns out, is that we trust our computers mostly because we have no other choice. Most of us wouldn’t know how to check if a computer is constructed correctly; and those of us who do are overwhelmed by the millions of lines of source code and billions of transistors packed into a typical computer. If you’re like me, this answer is dissatisfying. Precursor is our attempt to help the community develop a better one. Read the full update.

$375,157 raised

of $220,000 goal

170% Funded! Order Below

Product Choices



One fully assembled and tested Precursor. Includes a debug interface but no USB Type-C cable or charger.


Sutajio Kosagi

Sutajio Ko-usagi supports and produces open hardware products designed by bunnie and xobs.


Sean Cross

See Also

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