Bluetooth is everywhere, but it’s hard to inspect. Most of the magic is done inside a Bluetooth controller chip, accessed only through a controller-specific Host-Controller Interface (HCI) protocol, ...

Using Bluetooth on a desktop computer is now such a seamless process; it’s something built-in and just works. Behind that ubiquity is a protocol layer called HCI, or Host Controller Interface, a set ...

Nailing the basics.

Update 3/9/25: After receiving concerns about the use of the term 'backdoor' to refer to these undocumented commands, we have updated our title and story. Our original story can be found here. The ...

The cheap WLAN and Bluetooth chips from the manufacturer Espressif, ESP32, contain undocumented commands in the Bluetooth hardware communication in current firmware versions. This opens up a security ...

The Waveshare ESP32-P4-Nano is a tiny, inexpensive, low-power development board powered by a dual-core RISC-V processor. Available now from Waveshare or AliExpress for around $19 and up, the little ...

The cheapest boards might not be worth it.