In context: Smartphones have evolved to the point where we are basically carrying a reasonably capable miniaturized PC in our pockets. However, mobile operating systems are limited and unable to run desktop apps.

Planet Computers is changing the typical paradigm of a closed mobile-OS ecosystem. On Monday, it released a firmware update to its £665.83 ($860) Cosmo Communicator that allows users to install regular or rooted Debian Linux side-by-side with Android. The company had promised this feature was coming when it launched the stylish foldable in December 2018.

Now, users can partition the Cosmo’s storage and install Linux or TWRP. A boot menu will allow users to select which OS they want to use, and the secondary operating system will not interfere with over-the-air Android updates. The firmware is available for free for those willing to go through the trouble.

Planet Computers has provided a support page for getting the custom Linux distro installed, and as you might expect, it’s not really for the novice user. The smartphone’s system storage must be repartitioned, which will lose all the phone’s data. Some familiarity with the Linux command line is also required.

Running Linux on a smartphone does have some obvious limitations, particularly by way of input. The Cosmo is a slick-looking phone with a foldout mechanical QWERTY keyboard, but Planet Computers did not mention it having mouse support. Users will have to use the 6-inch OLED touchscreen for cursor input, which might not be ideal.

Secondary operating systems are limited right now, but when Planet Computers introduced the Cosmo at CES 2019, it said it working on versions of Kali Linux, Ubuntu Touch, and Sailfish. Still, having a functioning Linux minicomputer in your pocket is a pretty nifty, albeit geeky, gimmick.