Show HN: Hacking a $20 4G wireless hotspot into a texting device

A $20 4G wireless hotspot was repurposed into a texting device, defying conventional wisdom and supply chain constraints. The project's centerpiece was a 4G modem with WiFi, Bluetooth, a display, battery power, and complete unlockability, all for under $20. This modem served as the foundation for the hacking endeavor. The hacker found a display from the original device, but abandoned it in favor of LED-s for a more affordable solution.

The Linux operating system was easily installed using the openstick project. Although the Android device ran out of the box, access to the device tree proved invaluable. Custom code flashing was not deemed necessary for the current project. The keyboard utilized was a Clicks keyboard, which required substantial investment to achieve a desirable outcome.

The device's protocol was consistent with MFi devices, functioning as a standard USB keyboard with an additional proprietary endpoint for iPhone authorization. The custom PCB designed for the project managed USB host mode power, switching between host and device modes, display power, and signal level conversion. Despite initial uncertainties regarding the MF800's onboard components, the final PCB proved functional, powering the 4G modem and USB connection.

The USB connection, initially doubted due to potential via nicks, operated flawlessly with no issues.