Reverse Engineered Grill Controller Gets Open Firmware

August 18, 2026 by Fenix Guthrie 11 Comments

If you are a regular reader, then the odds are you have taken apart an electronic gadget, either for a fix, or simply because your curiosity got the better of you. Once inside, it’s all but impossible to help yourself from doing at least a little reverse engineering. That’s what happened when [PRBS23] took a look inside a MasterBuilt Gravity 800 Grill for a simple wire fix. But one thing led to the next, and now open source firmware for the grill is freely available!

The first order of business in creating the firmware is reverse engineering the original controller. Opening it up immediately reveals an ESP-32 and a well-labeled programming port. The rest of the control board is equally simple, including connectors for four thermistor temperature sensors, lid open/close switch, fan driver, 16 segment LCD, piezo buzzer, and some physical inputs.

The thermistor along with the physical inputs are connected to a 16 pin chip, interfacing with the MCU over a 9600 baud UART connection. [PRBS23] cannot determine an ADC chip meeting these specifications, so the most likely answer is a cheap MCU programmed to act as a simple analog fronted.

The neatly labeled programming header is used to quite easily dump the firmware with the espflash utility. Analyzing this dump reveals a rather strange ADC correction function used by the original firmware. The necessity and overall utility of this function remains unclear, does corrects a maximum of around 40 degrees Fahrenheit.

Most of the other features ended up being at least somewhat easier. The CS1621 segmented display driver is reasonably well documented with datasheets making its implementation far easier. Likewise, the other odds and ends were implemented in a far more normal manner compared to the thermistors.

All this reverse engineering work got tied together into a neat little firmware package. It comes with over the air updates PID controlled temperature, and a real-time web interface. This also isn’t the first time we have seen an IoT device liberated from proprietary firmware, and this remains one of our favorite uses of reverse engineering!

Pocket-Sized E-Ink Gets A Firmware Upgrade

April 5, 2026 by Matt Varian 26 Comments

Not so long ago, e-ink devices were rare and fairly pricey. As they have become more common and cheaper, some cool form-factor devices have emerged that suffer from subpar software. [Concretedog] picked up just such a device, and that purchase led to the discovery of a cool open-source firmware project for this tiny gadget.

[Concretedog] described the process of loading the firmware, which is just about as easy a modification as one can make. You plug the e-ink display into your computer, visit a website, and can flash it right from there. Once the display is running the CrossPoint Reader firmware, it unlocks some new tricks on this affordable reader. The firmware lets you turn the device into a WiFi hotspot and upload books wirelessly, or it can connect to an existing network to add files that way. It also enables rotating the display and KOReader syncing if you have multiple devices you read from.

We love seeing the community step in and improve devices that are hardware-wise good, sometimes great, but come up lacking in the software or firmware department. Thanks [Concretedog] for sharing your experience with this device and the cool open-source firmware. Be sure to check out some other projects we’ve featured where a firmware swap breathed new life into the hardware.

The Unexpected Joys Of Hacking An Old Kindle

November 24, 2025 by Tom Nardi 24 Comments

In the closing hours of JawnCon 0x2, I was making a final pass of the “Free Stuff for Nerds” table when I noticed a forlorn Kindle that had a piece of paper taped to it. The hand-written note explained that the device was in shambles — not only was its e-ink display visibly broken, but the reader was stuck in some kind of endless boot loop. I might have left it there if it wasn’t for the closing remark: “Have Fun!”

Truth is, the last thing I needed was another Kindle. My family has already managed to build up a collection of the things. But taking a broken one apart and attempting to figure out what was wrong with it did seem like it would be kind of fun, as I’d never really had the opportunity to dig into one before. So I brought it home and promptly forgot about it as Supercon was only a few weeks away and there was plenty to keep me occupied.

The following isn’t really a story about fixing a Kindle, although it might seem like it on the surface. It’s more about the experience of working on the device, and the incredible hacking potential of these unassuming gadgets. Whether you’ve got a clear goal in mind, or just want to get your hands dirty in the world of hardware hacking, you could do far worse than picking a couple of busted Kindles up for cheap on eBay.

If there’s a singular takeaway, it’s that the world’s most popular e-reader just so happens to double as a cheap and impressively capable embedded Linux development environment for anyone who’s willing to crack open the case.

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Hacking The Bluetooth-Enabled Anker Prime Power Bank

August 14, 2025 by Maya Posch 36 Comments

Selling power banks these days isn’t easy, as you can only stretch the reasonable limits of capacity and output wattage so far. Fortunately there is now a new game in town, with ‘smart’ power banks, like the Anker one that [Aaron Christophel] recently purchased for reverse-engineering. It features Bluetooth (BLE), a ‘smart app’ and a rather fancy screen on the front with quite a bit of information. This also means that there’s a lot to hack here beyond basic battery management system (BMS) features.

As detailed on the GitHub project page, after you get past the glue-and-plastic-clip top, you will find inside a PCB with a GD32F303 MCU, a Telink TLSR8253 BLE IC and the 240×240 ST7789 LCD in addition to a few other ICs to handle BMS functions, RTC and such. Before firmware version 1.6.2 you can simply overwrite the firmware, but Anker added a signature check to later firmware updates.

The BLE feature is used to communicate with the Anker app, which the official product page advertises as being good for real-time stats, smart charging and finding the power bank by making a loud noise. [Aaron] already reverse-engineered the protocol and offers his own alternative on the project page. Naturally updating the firmware is usually also done via BLE.

Although the BLE and mobile app feature is decidedly a gimmick, hacking it could allow for some interesting UPS-like and other features. We just hope that battery safety features aren’t defined solely in software, lest these power banks can be compromised with a nefarious or improper firmware update.

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Open Source Framework Aims To Keep Tidbyt Afloat

March 29, 2025 by Tom Nardi 10 Comments

We recently got a note in the tips line from [Tavis Gustafson], who is one of the developers of Tronbyt — a replacement firmware and self-hosted backend that breaks the Tidbyt smart display free from its cloud dependency. When they started the project, [Tavis] says the intent was simply to let privacy-minded users keep their data within the local network, which was itself a goal worthy enough to be featured on these pages.

But now that Tidbyt has been acquired by Modal and has announced they’ll no longer be producing new units, things have shifted slightly. While the press release says that the Tidbyt backend is going to stay up and running for existing customers, the writing is clearly on the wall. It’s now possible that the Tronbyt project will be able to keep these devices from ending up in landfills when the cloud service is inevitably switched off, especially if they can get the word out to existing users before then.

What’s that? You say you haven’t heard of Tidbyt? Well, truth be told, neither had we. So we did some digging, and this is where things get really interesting.

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Fighting To Keep Bluetooth Thermometers Hackable

January 16, 2025 by Tom Nardi 39 Comments

Back in 2020, we first brought you word of the Xiaomi LYWSD03MMC — a Bluetooth Low Energy (BLE) temperature and humidity sensor that could be had from the usual sources for just a few dollars each. Capable of being powered by a single CR2032 battery for up to a year, the devices looked extremely promising for DIY smart home projects. There was only one problem, you needed to use Xiaomi’s app to read the data off of the things.

Enter [Aaron Christophel], who created an open source firmware for these units that could easily be flashed using a web-based tool from a smartphone in BLE range and opened up all sorts of advanced features. The firmware started getting popular, and a community developed around it. Everyone was happy. So naturally, years later, Xiaomi wants to put a stop to it.

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Custom Firmware Adds Capabilities To Handie Talkie

January 3, 2025 by Bryan Cockfield 59 Comments

Although ham radio can be an engaging, rewarding hobby, it does have a certain reputation for being popular among those who would fit in well at gated Florida communities where the preferred mode of transportation is the golf cart. For radio manufacturers this can be a boon, as this group tends to have a lot of money and not demand many new features in their technology. But for those of us who skew a bit younger, there are a few radios with custom firmware available that can add a lot of extra capabilities.

The new firmware is developed by [NicSure] for the Tidradio TD-H3 and TD-H8 models and also includes a browser-based utility for flashing it to the radio without having to install any other utilities. Once installed, users of these handheld radios will get extras like an improved S-meter and detection and display of CTCSS tones for repeater usage. There’s also a programmer available that allows the radio’s memory channels to be programmed easily from a computer and a remote terminal of sorts that allows the radio to be operated from the computer.

One of the latest firmware upgrades also includes a feature called Ultra Graph which is a live display of the activity on a selected frequency viewable on a computer screen. With a radio like this and its upgraded firmware, a lot of the capabilities of radios that sell for hundreds of dollars more can be used on a much more inexpensive handheld. All of this is possible thanks to an on-board USB-C interface which is another feature surprisingly resisted by other manufacturers even just for charging the batteries.

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