Open-source Bitcoin mining: what it is and why it matters

Three things are open, and all three have to be for the term to hold:

• The hardware. Schematic, board layout and bill of materials are public, for the original Bitaxe in the skot/bitaxe repository and for the Gamma in bitaxeorg/bitaxeGamma. Anyone can rebuild the board, modify it or check that the delivered device matches the design. That is exactly how Nerdaxe, NerdQaxe and NerdOctaxe came about. The current exception is the Nerdaxe Gaia: its board files have not been published yet.
• The firmware. ESP-Miner runs on the miner’s ESP32-S3 and controls ASIC, fan, Wi-Fi and the stratum connection; the web interface on top is called AxeOS. The Nerd devices use NerdOS, their own branch of the same family. The source code is public, every release has release notes, and you flash it yourself, with us in the browser via flasher.bitaxe.de. OSM-OS, our optimised builds based on AxeOS and NerdOS, is preselected there; you can pick the unmodified originals at any time.
• The protocol. The miner speaks stratum with any pool and any node of your own. Since AxeOS 2.14 and NerdOS 1.0.37 that includes Stratum V2: the connection is encrypted and the pool identifies itself with a key. There is no cloud account, no registration and no manufacturer server between you and the Bitcoin network.

What is not open, on any miner in the world, is the ASIC itself: the BM1370 and BM1373 come from Bitmain, and their internals remain a trade secret. Open-source mining starts where you can take control: everything around the chip.

Open does not mean free of rights. The Bitaxe hardware is licensed under the CERN Open Hardware Licence version 2 in its strongly reciprocal variant (CERN-OHL-S-2.0), as are the Bitaxe GT and NerdQaxe boards. The ESP-Miner and NerdOS firmware are licensed under the GNU General Public License 3.0 (GPL-3.0). Both licences let you use, modify, rebuild and even sell the files. The condition: anyone who passes on a modified design or modified firmware must publish the sources under the same licence. That way every improvement stays open for everyone.

That also explains why so many manufacturers offer devices based on the Bitaxe design: it is explicitly allowed. As a buyer, what matters is therefore components, cooling, power supply, warranty and support. What role trademark rights play for the Bitaxe name is described in our article Who owns the Bitaxe?

The factory hashrate is what each firmware calculates from clock, cores and chips; in operation it sits a little above or below depending on the device.

On top of that come boards the official firmware already knows but we do not carry: Gamma Duo (board 650, two BM1370 on 5 V), Naja Duo (1201, two BM1372/BM1373) and Gamma Hex (1300, six BM1370). One firmware for many series is one of the big advantages of the open approach.

We sell both, so the difference can be shown with two devices from our own range. The Avalon Nano 3S from Canaan is a closed device: 6 TH/s at 140 W, it runs reliably, but firmware and board cannot be inspected, updates come only from the manufacturer, and if Canaan ends support the device stays where it is. The Bitaxe Gamma is the opposite: around 1.1 to 1.2 TH/s at about 17 W, open board, open firmware, replaceable fan, cooler and display, updates from the community.

Why this is more than principle is shown by a case from 2017: the firmware of the Antminer series contained a function (“Antbleed”) with which the manufacturer could have shut devices down remotely. With open firmware, something like that would have been noticed on the day of the commit. On the Bitaxe anyone who wants to reads what the device does, and the community does so with every release.

The Bitaxe is the reference design that Skot started as an open project in 2022: a Bitmain ASIC on an open board, driven by an ESP32-S3. Further boards grew out of it. The Nerdaxe line (Nerdaxe Gamma with a large display, Nerdaxe Gaia with the BM1373) comes from BitMaker’s circle, NerdQaxe with four and NerdOctaxe with eight chips from the circle around shufps, who also maintains the NerdOS firmware. Bitaxe devices run AxeOS, the Nerd devices NerdOS; both are branches of the same firmware family, use the same pool values and are updated through the same web flasher.

What that means for you: pool values, terms and tools apply to all devices, and if a board goes out of production the firmware keeps running anyway. Which device fits which setup is compared in Bitaxe or Nerdaxe, and what exactly a Bitaxe is, is explained in the Bitaxe miner guide.

Bitcoin is only as decentralised as its infrastructure. Hashrate concentrates in large farms, the hardware comes from a few manufacturers, and the firmware of that hardware is closed. Open-source mining addresses all three points: it brings hashrate into living rooms instead of warehouses, it makes the devices reproducible, and it makes the software auditable. A single Bitaxe does not change the statistics. Tens of thousands of Bitaxes, each with its own address and optionally its own node, are a different part of the network than a farm with the same hashrate.

Add the sovereignty of the individual: anyone who connects their miner to their own node (Public Pool on Umbrel) builds their own block template, and no pool decides any more which transactions go into the block. With solo mining a find also goes entirely to your own address. Both are technically possible with closed devices; with open ones they are a given.

Open does not mean more profitable. At the difficulty of 26 September 2026 a Bitaxe Gamma has about a 1 in 16,900 chance per year at a block, for around €45 of electricity; its expected value of around €14 is below that (the maths: Finding a block with a Bitaxe, your device: mining calculator). Open also does not mean more finished: the Bitaxe is an open board with a fan, not a case with one-button operation. In return it is set up in ten minutes and can be changed in every respect. If you want a device you plug in and never look at again, the Avalon Nano is right for you. If you want to know what your miner does, the Bitaxe.

1. Pick a device: Bitaxe Gamma for the quiet entry, Nerdaxe Gaia for the best efficiency, NerdQaxe++ for more chance. The overview is in Buy a Bitcoin miner.
2. Set up: connect Wi-Fi, then enter the pool values from the pool configurator on the Pool page in AxeOS. The guide is in Set up a Bitaxe.
3. Understand: AxeOS explained names the normal value for every readout.
4. Go further: your own node with Umbrel, encrypted mining with Stratum V2, firmware updates via the web flasher, overclocking following the overclocking guide.