Umbrel OS is the operating system of Umbrel Bitcoin and Lightning node. It's based on Raspberry Pi OS (formerly Raspbian) and uses [pi-gen](https://github.com/RPi-Distro/pi-gen) for customization.
Umbrel OS currently supports Raspberry Pi 3 and 4. If you'd like to run it on any other hardware, please [create an issue](https://github.com/getumbrel/umbrel-os/issues/new/choose) or drop us a message in our [community chat](https://t.me/getumbrel). We'll gladly consider your request.
1. Download the [latest release of Umbrel OS](https://github.com/getumbrel/umbrel-os/releases/latest), or [build the image from source](#-build-umbrel-os-from-source).
> If you're running Umbrel OS on Bitcoin mainnet (default), the external SSD or HDD should be at least 500 GB in size (we recommend 1 TB+) so it can store the whole Bitcoin blockchain. If you do not have access to a large drive, Umbrel OS will still work by automatically enabling [pruning](https://bitcoin.org/en/full-node#reduce-storage), although you will lose access to some features.
Other Raspbian-related stuff can be found in [Raspbian's documentation](https://github.com/RPi-Distro/pi-gen/blob/master/README.md) which is still applicable.
> Umbrel is still in an early stage and things are expected to break every now and then. We **DO NOT** recommend running it on mainnet with real money just yet, unless you want to be really *#reckless*.
If you're a developer looking to help but not sure where to begin, check out [these issues](https://github.com/getumbrel/umbrel-os/issues?q=is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22) that have specifically been marked as being friendly to new contributors.
If you're looking for a bigger challenge, before opening a pull request please [create an issue](https://github.com/getumbrel/umbrel-os/issues/new/choose) or [join our community chat](https://t.me/getumbrel) to get feedback, discuss the best way to tackle the challenge, and to ensure that there's no duplication of work.