I have a drawer full of old phones. They sit there, forgotten, between the spare charging cables and the mystery adapters I am afraid to throw away. Each one was perfectly good when I upgraded, but what do you do with a three-year-old Android phone? Sell it for $40 and feel like you got cheated? Give it to a relative who does not want it? Recycle it and admit defeat? There is a fourth option, and it is the one I have landed on: turn the old phone into a dedicated single-purpose computer, keep it plugged in next to a real screen, and treat it like a tiny Linux box.
I am writing this article on a Pixel 5 from 2020, plugged into a portable monitor, paired with a Bluetooth keyboard and mouse. The phone is running a custom Android image that boots straight into a desktop-style UI. It does most of what my laptop does for the things I do most: writing, reading, browser-based work, light development. It cost $0 because I already owned the phone. The portable monitor was $90. The whole setup is slower than my laptop, has a smaller screen, and runs Android. It is also the device I reach for first when I sit down at the kitchen table with a coffee.
The idea is not new
The “use a phone as a desktop” concept has been around since the first Samsung DeX (a Samsung feature that projects a desktop-style interface when you connect a phone to an external display) launched in 2017. DeX works, but it is locked to recent Samsung phones. The “your phone is your computer” pitch from companies like Motorola and Huawei has never quite taken off. The hardware is there, but the software has always been the bottleneck.
What changed in 2025 is that there are now a handful of custom Android images that turn any phone with a USB-C port (a small oval-shaped connector used for charging and data on modern phones and laptops) and a decent processor into something that genuinely behaves like a Linux desktop. The two I have spent real time with are PostmarketOS, a Linux distribution built specifically for phones, and Maru OS, a Debian-based Android variant that boots into a Linux desktop when you connect an external display. PostmarketOS is the cleaner experience for someone who already knows Linux. Maru OS is the easier setup if you want a turnkey image.
I went with PostmarketOS because I am the kind of person who would rather spend four hours on the setup than $200 on a refurbished ThinkPad. The trade is real. You should know what you are getting into before you start.
What I actually did
The hardware side took about 20 minutes. I bought a 15.6-inch portable monitor with a built-in kickstand (a small folding support that lets the monitor stand on a desk without a separate mount) and USB-C input for $90, a $15 Bluetooth keyboard, and a $10 mouse. The Pixel 5 I already had. I plugged the phone into the monitor with a USB-C cable, paired the keyboard and mouse, and turned the whole thing on. The phone detected the external display and started outputting video.
The software side took longer. PostmarketOS does not have a Pixel 5 image out of the box, so I had to compile a custom build using their pmbootstrap (a command-line tool that handles the build process for PostmarketOS) tool. The build took about 90 minutes on my laptop. Flashing the image to the phone took another 20 minutes. There were two boot loops (the phone restarted twice instead of loading the OS) before I got the right combination of kernel (the core program that handles communication between the operating system and the phone’s hardware) and graphics driver, which is the moment I learned that the Pixel 5’s Adreno 640 GPU (the graphics processing unit, the chip that renders what you see on screen) has spotty mainline Linux support. The third attempt booted, and I have not touched the software setup since.
Once it boots, you get a real Linux desktop. Weston is the default compositor (the part of a Linux desktop that draws windows, handles transparency, and passes keyboard and mouse input to the apps). There is no Gnome or KDE (two of the most common Linux desktop environments, the collections of menus, panels, and apps that make up a graphical user interface) in the default PostmarketOS phone image. I installed Sway, a tiling window manager (a program that arranges open windows in a non-overlapping grid so each app fills its own section of the screen), and a few GTK apps (apps built with GTK, a common Linux toolkit for drawing graphical interfaces). Firefox runs. The terminal runs. Vim runs. None of this is fast, but it is functional.
What works and what does not
After two months of daily use, here is the honest score.
- Web browsing. Firefox is usable. Pages load in 2-4 seconds over Wi-Fi. Heavy sites like YouTube work but stutter. I have not tried video calls.
- Writing. I wrote two long articles and most of this one on the phone. The Bluetooth keyboard has enough latency (a slight delay between pressing a key and the letter appearing on screen) to be noticeable, but not enough to slow me down. The screen is small but readable.
- Terminal work. SSH (a secure command-line connection to a remote machine), git, and vim all work. The on-screen terminal is fine. I have not tried compiling anything heavy.
- Media. Local video plays fine up to 1080p. Streaming services do not work well because the DRM (digital rights management, the copy-protection that streaming services use to prevent piracy) in browser-based players does not always recognize the unusual user agent string (the text a web browser sends to a website to identify itself and its capabilities) that PostmarketOS sends.
The slow parts are the ones you would expect. The Pixel 5 is a 2020 phone, and even though it is fast by phone standards, it is slow by 2025 laptop standards. Compiling software is painful. Web pages with too many images stutter. Anything that touches the GPU is rough. The battery life is the most surprising problem. With the screen on full brightness and the keyboard connected, the phone lasts about 3 hours. The fix is to keep it plugged in, which I do anyway because it is a desktop setup.
The biggest functional gap is the lack of a real desktop file manager. Files in Android are sandboxed (each app is restricted to its own private storage, with limited access to other apps’ files), and the Linux user space (the layer of the operating system that user applications run in, as opposed to the privileged kernel layer) on PostmarketOS does not have a great answer for that. I use adb (the Android Debug Bridge, a command-line tool for communicating with Android devices) to push files over USB. It is fine for a developer. It is not fine for a non-technical user.
Trade-offs
This is not a replacement for a real computer. The phone is slower than a $200 used ThinkPad from 2018, and the ThinkPad would have a real keyboard, a real trackpad, a real desktop OS, and battery life measured in hours. The argument for the phone-as-PC is not that it is better. The argument is that you already own the phone, and the cost of turning it into a usable second device is $115, which is less than the cheapest refurbished laptop worth buying.
The second cost is the software learning curve. PostmarketOS is for people who already know how to flash a phone, compile a Linux kernel, and debug a boot loop. If that sentence did not make sense, this project is not for you. The barrier to entry is real, and the documentation is sparse in places. Expect to spend a weekend on the setup.
The third cost is the lack of polish. The desktop is functional, not pretty. There are visual glitches, especially around screen rotation and external display hot-plug (plugging the monitor in or out while the phone is running). The keyboard mapping is not quite right. The mouse pointer is the size of a quarter on a 15-inch screen. None of these are dealbreakers, but they are not what you would call “consumer-ready.” This is a hobby project, not a product.
If you have an old flagship phone from the last 5 years, a USB-C cable, and a weekend to spare, the experiment is worth it. You will learn something about the hardware you already own, end up with a usable second device, and probably spend less than $150 doing it. If you want something that just works, buy a refurbished ThinkPad.
What I would tell past me
If I could send a message back to the version of me pulling the Pixel 5 out of the drawer two months ago, I would say four things.
- Buy the right portable monitor first. I started with a 13-inch panel and it was too small. 15.6 inches at 1080p is the sweet spot. Spend the extra $30.
- Do not bother with PostmarketOS on a phone older than 2018. The kernel support gets worse with every generation. A 2020+ phone is the minimum for a usable experience.
- Plan for the keyboard latency. Bluetooth is the easy option. A wired USB-C keyboard works better but looks weird. The lag is real but tolerable after a day of use.
- Keep your expectations in check. This is a usable second device, not a laptop replacement. The phone is great for writing, reading, and browser-based work. It is not great for video, image editing, or anything GPU-heavy.
The drawer full of old phones is now empty. The Pixel 5 is plugged in next to the kitchen monitor, paired with a Bluetooth keyboard, and running PostmarketOS. It is not the fastest computer in the house. It is the one I reach for first.