Before you start
What you'll end up with, what it protects you from, and what it doesn't.
- 10 min
What you’ll end up with
A small hardware wallet you put together yourself: a Raspberry Pi Zero 2 W with a 1.3-inch screen and a joystick on top. It runs the open-source firmware of the OneKey Classic, and it plugs into your computer with one USB cable.
On the computer you use the OneKey desktop app, built from its source code by you. The app shows balances and prepares transactions. The device keeps your keys, shows you what you are about to sign, and signs only after you press its button.
Why build one yourself
A wallet you buy passes through a factory, a warehouse and a courier before it reaches you. Most people trust that chain. If you’d rather not have to, you can build one from general-purpose parts that are sold by the million for other uses, and put every piece of software on it yourself.
Nothing on it is a black box. The firmware and the app both come from public source code. You download it, can read it, and compile it on your own machines.
What it can’t do
Be clear about these before you put money on it.
- It runs an older firmware version. The guide uses OneKey Classic firmware 3.12.0 from June 2025, because that is the newest version whose code can be built for a computer like the Raspberry Pi. Current Classic devices run newer firmware.
- The OneKey app will say the device is not genuine. That is correct: it wasn’t made by OneKey. Your own build of the app skips that check.
- It connects by USB only. There is no Bluetooth and no phone app support.
- You are responsible for it. There is no support line. Start with a small amount and keep it small until you’ve tested a full restore.
What you need
- The parts on the next page, about $38 to $57 in total.
- A computer with macOS or Linux, 16 GB of memory and about 30 GB of free disk space. Building the app is the heaviest step. (A Windows computer can do every step on the Pi, but can’t build the app yet.)
- An internet connection during setup. The finished device never goes online.
- Pen and paper for your recovery phrase.
- About 5 hours, spread over a day or two. Most of it is waiting for things to download and compile.
You don’t need to solder or to know how to program. Every command is on the page with a copy button. If you can copy, paste and press Enter, you can build this.
Choose your options
Before you start, pick your options on Your build. The commands in every step change to match what you choose.