There are a number of cheap “4G LTE WiFi modems” available from Chinese devices makers are basically tiny computers/mobile routers powered by Qualcomm Snapdragon 410 processors and Android-based software.
But hackers have discovered that they can be modified to run mainline Linux software like Debian 11.
Chinese hacker HandsomeYingYan figured out that the bootloader of this little Android PC-on-a-stick is unlocked, which means that it’s pretty trivial to flash custom firmware to the modem, giving you more control over the device. The code and instructions contained in the OpenStick Project repository at GitHub, but documentation is in Chinese.
So developer Extrowerk translated the instructions to English. Basically you just need to install Google’s adb and fastboot tools on a computer, connect the modem to a USB port, then run a few commands to flash a custom bootloader and Debian to the stick.
Since the modem doesn’t have a display you’ll need to do the initial setup and configuration while it’s plugged into your computer. But once you set up ssh access, you should be able to connect to it over WiFi.
While there are many compatible USB LTE modems available from AliExpress and eBay, including some with microSD cards that can be used for additional storage, finding one that has the right specs can be a bit hit or miss. Some have different modems that aren’t as Linux-friendly, for example. And others may have limited support for 4G LTE networks in your region.
Fortunately Extrowerk points us to the stick they purchased: a model that sells for $12 (or 2 for $20) at AliExpress. While it looks like a chunky USB flash drive, it’s actually a modem with a Qualcomm Snapdragon 410 (MSM8916) quad-core ARM Cortex-A53 processor, 512MB of RAM and 4GB of eMMC storage plus support for 4G LTE download speeds up to 150MB/s and WiFi 4 connectivity.
I can’t tell from the product description what network bands are supported though, so it’s unclear what countries this model can be used in… although if you just want a customizable WiFi-enabled device and don’t care about cellular connectivity, HackADay notes that this little USB stick is about the same price as a Raspberry Pi Zero 2 W. And while it features fewer user-accessible ports, pins, and other connectors, it should offer comparable performance.