Interposer Helps GPS Receiver Overcome Its Age

We return to [Tom Verbeure] hacking on Symmetricom GPS receivers. This time, the problem’s more complicated, but the solution remains the same – hardware hacking. If you recall, the previous frontier was active antenna voltage compatibility – now, it’s rollover. See, the GPS receiver chip has its internal rollover date set to 18th of September 2022. We’ve passed this date a while back, but the receiver’s firmware isn’t new enough to know how to handle this. What to do? Build an interposer, of course.

You can bring the module up to date by sending some extra init commands to the GPS chipset during bootup, and, firmware hacking just wasn’t the route. An RP2040 board, a custom PCB, a few semi-bespoke connectors, and a few zero-ohm resistors was all it took to make this work. From there, a MITM firmware wakes up, sends the extra commands during power-on, and passes all the other traffic right through – the system suspects nothing.

Everything is open-source, as we could expect. The problem’s been solved, and, as a bonus, this implant gives a workaround path for any future bugs we might encounter as far as GPS chipset-to-receiver comms are concerned. Now, the revived S200 serves [Tom] in his hacking journeys, and we’re reminded that interposers remain a viable way to work around firmware bugs. Also, if the firmware (or the CPU) is way too old to work with, an interposer is a great first step to removing it out of the equation completely.

Cheap Hackable Smart Ring Gets A Command Line Client

Last year, we’ve featured a super cheap smart ring – BLE, accelerometer, heart sensor, and a battery, all in a tiny package that fits on your finger. Back when we covered it, we expected either reverse-engineering of stock firmware, or development of a custom firmware outright. Now, you might be overjoyed to learn that [Wesley Ellis] has written a Python client for the ring’s stock firmware.

Thanks to lack of any encryption whatsoever, you can simply collect the data from your ring, no pairing necessary, and [Wesley]’s work takes care of the tricky bits. So, if you want to start collecting data from this ring right now, integrate it into anything you want, such as your smart home or exoskeleton project, this client is enough. A few firmware secrets remain – for instance, the specific way that the ring keep track of day phases, or SPO2 intricacies. But there’s certainly enough here for you to get started with.

This program will work as long as your ring uses the QRing app – should be easy to check right in the store listing. Want to pick up the mantle and crack open the few remaining secrets? Everything is open-source, and there’s a notepad that follows the OG reverse-engineering journey, too. If you need a reminder on what this ring is cool for, here’s our original article on it.

An excerpt from the website, showing the nRootTag block diagram and describing its structure

Hijacking AirTag Infrastructure To Track Arbitrary Devices

In case you weren’t aware, Apple devices around you are constantly scanning for AirTags. Now, imagine you’re carrying your laptop around – no WiFi connectivity, but BLE’s on as usual, and there’s a little bit of hostile code running at user privileges, say, a third-party app. Turns out, it’d be possible to make your laptop or phone pretend to be a lost AirTag – making it and you trackable whenever an iPhone is around.

The nroottag website isn’t big on details, but the paper ought to detail more; the hack does require a bit of GPU firepower, but nothing too out of the ordinary. The specific vulnerabilities making this possible have been patched in newer iOS and MacOS versions, but it’s still possible to pull off as long as an outdated-firmware Apple device is nearby!

Of course, local code execution is often considered a game over, but it’s pretty funny that you can do this while making use of the Apple AirTag infrastructure, relatively unprivileged, and, exfiltrate location data without any data connectivity whatsoever, all as long as an iPhone is nearby. You might also be able to exflitrate other data, for what it’s worth – here’s how you can use AirTag infrastructure to track new letter arrivals in your mailbox!

Here’s A Spy Movie-Grade Access Card Sniffing Implant

Some of our devices look like they’re straight out of hacker movies. For instance, how about a small board you plant behind an RFID reader, collecting access card data and then replaying it when you next walk up the door? [Jakub Kramarz] brings us perhaps the best design on the DIY market, called The Tick – simple, flexible, cheap, tiny, and fully open-source.

Take off the reader, tap into the relevant wires and power pins (up to 25V input), and just leave the board there. It can do BLE or WiFi – over WiFi, you get a nice web UI showing you the data collected so far, and letting you send arbitrary data. It can do Wiegand like quite a few open-source projects, but it can also do arbitrary clock+data protocols, plus you can just wire it up quickly, and it will figure out the encoding.

We could imagine such a board inside a Cyberpunk DnD rulebook or used in Mr Robot as a plot point, except that this one is real and you can use it today for red teaming and security purposes. Not to say all applications would be NSA-catalog-adjacent pentesting – you could use such a bug to reverse-engineer your own garage door opener, for one.

Sensory Substitution Device Tingles Back Of Your Hand

A team from the University of Chicago brings us a new spin on sensory substitution, the “Seeing with the Hands” project, turning external environment input into sensations. Here specifically, the focus is on substituting vision into hand sensations, aimed at blind and vision disabled. The prototype is quite inspiration-worthy!

On the input side, we have a wrist-mounted camera, sprinkled with a healthy amount of image processing, of course. As for the output, no vibromotors or actuators are in use – instead, tactile receptors are stimulated by passing small amounts of current through your skin, triggering your touch receptors electrically. An 5×6 array of such “tactile” pixels is placed on the back of the hand and fingers. The examples provided show it to be a decent substitution.

This technique depends on the type of image processing being used, as well as the “resolution” of the pixels, but it’s a fun concept nevertheless, and the study preprint has some great stories to tell. This one’s far from the first sensory substitution devices we’ve covered, though, as quite a few of them were mechanical in nature – the less moving parts, the better, we reckon!

A plugged-in 12VHPWR cable, with two thermistors inserted into the connector shell, monitoring for heat

12VHPWR Watchdog Protects You From Nvidia Fires

The 12VHPWR connector is a hot topic once again – Nvidia has really let us down on this one. New 5080 and 500 GPUs come with this connector, and they’re once again fire-prone. Well, what if you’re stuck with a newly-built 5080, unwilling to give it up, still hoping to play the newest games or run LLMs locally? [Timo Birnschein] has a simple watchdog solution for you, and it’s super easy to build.

All it takes is an Arduino, three resistors, and three thermistors. Place the thermistors onto the connector’s problematic spots, download the companion software from GitHub, and plug the Arduino into your PC. If a temperature anomaly is detected, like one of the thermistors approaching 100C, the Arduino will simply shut down your PC. The software also includes a tray icon, temperature graphing, and stability features.  All is open-source — breadboard it, flash it. You can even add more thermistors to the mix if you’d like!

This hack certainly doesn’t just help protect you from Nvidia’s latest creation – it can help you watch over any sort of potentially hot mod, and it’s very easy to build. Want to watch over connectors on your 3D printer? Build one of these! We’ve seen 12VHPWR have plenty of problems in the past on Nvidia’s cards – it looks like there are quite a few lessons Nvidia is yet to learn.

FOSDEM 2025, A Hardware Hacker’s Haven

Have you been to FOSDEM? It’s a yearly two-day megaconference in Brussels, every first weekend of February. Thousands of software and hardware hackers from all across Europe come here each year, make friends, talk software and hardware alike, hold project-specific meetups to drink beer and talk shop, and just have a fun weekend surrounded by like-minded people.

In particular, FOSDEM has free admission – drop by for the weekend, no need to buy entry tickets, just sort out your accomodation, food, travel, and visit for a day or two. I’ve covered FOSDEM quite extensively in 2023, so if you want to know more about how it works, I invite you to check out that article – plenty of stories, cool facts about FOSDEM, showcases, and so on. This year, I’ve also been to FOSDEM, it’s been pretty great, and I’d like to tell you about cool things I’ve seen happen during FOSDEM 2025.

FOSDEM is often described as an open software conference, and you might’ve had been fooled by this if you simply have checked the Wikipedia page. However, let me assure you – there’s always plenty of hardware, large amounts of it! This year, I feel like hardware has taken the spotlight in particular – let me show you at least some of it, so that you know what kinds of cool stuff you can expect and plan for in 2026.

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