András Tevesz Turns to a Nordic Semi nRF52840 to Give the Flipper Zero Thread, Matter Support

Security researcher András Tevesz has given the Flipper Zero multitool support for Matter via Thread — by building an expansion board based around the Nordic Semiconductor nRF52840.

"For my integration project, the Thread protocol requires the introduction of a new SoC [System-on-Chip] with a radio chip," Tevesz explains of the decision to design a hardware add-on for the Flipper Zero. " Unfortunately, the code that manages the second core of the [Flipper Zero's internal] MCU — which is responsible for various radio protocols, including BLE [Bluetooth Low Energy], Zigbee, OpenThread, and others – is provided by ST[Microelectronics], the chip manufacturer, in the form of signed and encrypted binaries. This code is closed-source, and partners do not have access to its source code. I wanted to reduce the development time, so I chose a well-known platform for development and integrated Flipper with the [Nordic Semi] nRF52840 SoC."

The goal of Tevesz' project: adding support for the vendor-neutral Matter protocol over Thread radio networks to the Flipper Zero, Flipper Devices' popular yet controversial digital pet and "hacker's" electronic toolbox. As standard, the Flipper Zero can handle sub-gigahertz networks carrying a range of protocols, but it can't handle Matter — and without enough storage available in its integrated microcontroller to add Matter support without removing some other functionality, the solution was to follow in the footsteps of those adding Wi-Fi connectivity to the device and build an add-in board connecting to the general-purpose input/output (GPIO) header at the top.

"My work focuses on detecting and protecting against emerging threats associated with Thread networks," Tevesz explains of the thinking behind the project, which is built atop the OpenThread firmware. "I aimed to initiate TCP and UDP connections from the Thread network and track their routing. However, I discovered that no currently available devices can achieve this without building and coding a new firmware image for specific radios."

With the hardware add-on wired into the Flipper Zero's GPIO pins, Tevesz has achieved his goal — after a fashion. At the time of writing the radio could only be used when the Flipper Zero was connected to a more powerful PC and acting as a USB-UART bridge, making it effectively no different to just using the USB dongle at its heart directly. Tevesz aims to change that, though, with plans for a native Flipper Zero application that will provide support for capturing information from a Thread network as a standalone device.

The first three parts of the project write-up are available on the CUJO AI website, with the fourth part detailing the native Flipper Zero app to follow.