Blogger wrongbaud has created a three-part series of posts on hacking a cheap electric toothbrush bought on AliExpress and turning it into a Workshop tool, rather than something to clean your teeth with.
The first stage involves using a Raspberry Pi to set up OpenOCD, and then opening the toothbrush to identify its components, culminating in the discovery of a debug serial port, which can then be used to extract the firmware.
The second part of the blog sees wrongbaud using the serial port to access the SPI flash chip that holds the images for the toothbrush’s display, enabling him to find out how images are stored and to modify them.
The final part focuses on using OpenOCD again to extract the firmware, analyse it, modify it and then flash the modified version back to the hardware.
The posts are intended as a practical demonstration of the tools and concepts involved in reverse engineering.
