Practical overview
When it fits
Use the design when you want to build or adapt a small, standalone Bitcoin ASIC miner and are prepared to handle PCB assembly, cooling, power and firmware setup.
Who it is for
- Hardware builders interested in assembling an open Bitcoin ASIC miner.
- Bitcoin miners seeking a standalone Wi-Fi device for pool or solo mining.
- Developers adapting ESP-Miner firmware to supported BM1366 or BM1397 hardware.
Documented uses
- Build a compact Bitcoin ASIC miner from the published hardware design.
- Connect a miner to a pool over Wi-Fi without a separate computer.
- Adjust ASIC voltage and manage fan operation while monitoring input power.
- Use a standalone device for solo or pool mining.
Requirements & limits
The documented Ultra design is open source under CERN-OHL-S-2.0. The repository provides design files; it describes the build as advanced and notes that the hardware work has moved to model-specific repositories under bitaxeorg.
- The Ultra design uses a BM1366 ASIC; that chip has a different footprint and pinout from the BM1397 and BM1387 used in earlier Bitaxe revisions.
- Active cooling is required, and the board has a connector for a 5V fan.
- The repository specifies 5V DC only, approximately 15W, and a 5.5×2.1 mm center-positive barrel jack; another voltage can damage the device.
- The board includes an ESP32-S3, an INA260 power monitor, digital core-voltage adjustment, PWM fan control and an SSD1306 OLED interface.
- ESP-Miner is the firmware identified by the repository; its main branch is stated to support BM1366 and BM1397.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Prepare parts for a Bitaxe Ultra hardware build
Gather the documented hardware and power components for a Bitaxe Ultra build.
Before you start
- PCB fabrication access and the KiCad design files.
- The BM1366 ASIC and the other PCB components listed in the bill of materials.
- A heatsink, active 5V fan, and good-quality thermal compound.
- A 5V DC power supply rated for the miner’s 15W requirement; the README notes 25W (5V, 5A) supplies have worked well.
- The README links to building and assembly guidance for the next stages.
Steps
Use the Gerber files in the Manufacturing Files directory to order a 4-layer PCB and the top and bottom stencils.
Obtain the PCB components other than the ASIC using the BOM, and obtain a BM1366 ASIC.
Prepare a 40×40 mm heatsink and 5V fan, applying good-quality thermal compound between the heatsink and ASIC; active cooling is required.
Select a 5V DC-only supply with a 5.5×2.1 mm center-positive barrel connector and enough capacity for the 15W requirement.
Expected outcome
The documented PCB, components, cooling parts, and power supply are prepared for the build; the README points to building.md and assembly.md for PCB-ordering and assembly tips.
Guide limitations
- The README describes this as an advanced build and does not provide the detailed assembly procedure here.
- Do not use a supply other than 5V DC; the README warns that another voltage will damage the Bitaxe.
- The main repository says the hardware work has moved to model-specific repositories under bitaxeorg; confirm the appropriate model-specific materials before proceeding.
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 15 October 2026
- Original website title
- skot/bitaxe · Official homepage title · retained in its source language

