Install & set up Braiins OS (Antminer S19j Pro / S19k Pro)

Install & set up Braiins OS (Antminer S19j Pro / S19k Pro)

Braiins OS+ is the best-known alternative firmware for the Antminer S19 family. This guide explains what the firmware does, what to settle before installing, how the installation works in general, and how to set up pool, power target and monitoring afterwards. Braiins changes menus and versions regularly, so the current documentation on braiins.com is always the authoritative source.

What are Braiins OS and Braiins OS+?

Braiins OS is an open-source firmware for ASIC miners that replaces the manufacturer's stock firmware. It is based on Linux and developed by Braiins, the company behind Braiins Pool.

Braiins OS+ is the extended variant with autotuning. It adjusts frequency and voltage per chip instead of running all chips at the same values. Braiins charges a small developer fee for this; the current terms are on braiins.com.

Both are third-party firmware and not part of Bitmain's manufacturer specification. Braiins OS+ versions exist for the S19j Pro and S19k Pro; which one fits your control board, you check with Braiins before downloading.

Benefits: autotuning, efficiency and power limiting

These are the reasons operators switch to Braiins OS+. The result always depends on the individual unit and cannot be guaranteed.

• Autotuning: the firmware looks for a suitable operating point per chip. This can improve efficiency (J/TH) compared with the stock firmware.
• Power target: you set a wattage and the firmware regulates clock and voltage accordingly. This is handy when the electrical connection, an inverter or a PV surplus limits the available power.
• Underclocking for quieter operation: less power means less waste heat, and the fans usually have to work less. Our guide on making an Antminer quieter covers the rest of the noise question.
• More insight: the web interface shows hashrate, temperatures, fans and power clearly, and several miners can be managed together with Braiins Toolbox.

Requirements before installing

Settle these points before you replace the stock firmware:

• Network: the miner is connected to the router by LAN cable and runs stably on the stock firmware. Pool access and password are written down.
• IP address: you know the miner's IP, for example from your router's device list. Our Antminer setup guide explains how.
• Matching firmware: model, hardware version and control board match the Braiins version. Only download the firmware from braiins.com.
• Computer on the same network: a PC or laptop on the same network if you use Braiins Toolbox or the upload via the web interface. For the SD card route you also need a card and a card reader.
• Stable power: never interrupt the installation with a power cut or by pulling the mains cable.
• Operating environment: check that circuit, cooling and intake air suit the power level at which you plan to run the miner later.

Risks and warranty

Third-party firmware intervenes in the hardware's operating parameters. Higher power levels mean more waste heat and more wear, and a faulty installation can temporarily make the miner unusable.

For consumers the statutory warranty remains in place. However, there is no claim for damage demonstrably caused by mining software, overclocking, improper operation or insufficient cooling. The restrictions described in the notice apply to business customers. The details are in our mining software notice, which you should read before installing. If you do not want to bear that risk yourself, stay with the stock firmware.

Braiins also documents a way back to the stock firmware. Keep the matching firmware file from Bitmain ready and follow Braiins' current instructions.

Installing Braiins OS+ step by step

The exact procedure depends on the control board and the current firmware version. The steps below describe the general route; menu names and file names are in the Braiins documentation.

• Step 1: Secure your starting point. Let the miner run on the stock firmware and check that all three hashboards deliver hashrate. Write down pool URL, worker and password as well as the current IP address. That way you can tell later whether a fault comes from the installation or from the hardware.
• Step 2: Choose the matching firmware. On braiins.com, find the Braiins OS+ version for your model (S19j Pro or S19k Pro) and your control board. Read the notes for that version, especially any minimum requirements for the installed stock firmware, and download the file or installer only from there.
• Step 3: Choose an installation route. There are basically three routes. First, Braiins Toolbox: the program from Braiins runs on a PC, finds miners on the network and installs the firmware on one or several units. Second, a firmware upload via the web interface of the stock firmware, where you upload the Braiins file in the firmware update area. Third, on certain control boards, an SD card image: you write the image to a card, insert it in the powered-off miner and start it from the card as described. Which route works for you is in the Braiins documentation.
• Step 4: Start the installation and do not interrupt it. Start the installation via the chosen route. Keep the miner connected to power and network. During writing and the restart that follows, do not pull the mains cable or switch the miner off. This usually takes a few minutes.
• Step 5: Find the miner on the network again. After the restart the miner may get a new IP address. Check your router's device list or search the network with Braiins Toolbox. Then open the IP in a browser to see the Braiins OS+ web interface.
• Step 6: Log in and secure access. The default credentials of a freshly installed Braiins firmware are in the Braiins documentation. Set your own password straight away so nobody on the network can access the settings.
• Step 7: Set pool and power target, then observe. Enter your pool, set a power target and watch hashrate, temperatures and fans over the first hours. Autotuning needs some time until the values settle. How to set pool and power target is covered in the next section.

Setup: pool, power target, fans, monitoring

Enter your pool

In the pool settings you enter the stratum URL, the worker name and any password, just as with the stock firmware. Copy the URL from your pool's dashboard and, if possible, add a second pool as a fallback.

Pool fees are set by your pool and come on top, independent of the firmware. How the Braiins OS+ developer fee is calculated is stated on braiins.com.

Set the power target in watts

With autotuning you choose a power target in watts. Depending on the version there is also a hashrate target. The firmware sets clock and voltage so that the miner reaches this target as efficiently as possible.

Choose the value for your situation: for PV operation, base it on the surplus your inverter and connection provide. For quieter operation, go to a lower level and check how fans and temperature behave. The permitted range depends on model and version. Start conservatively and raise it only step by step.

Keep an eye on fans and temperature

Depending on the version you can set the target temperature and fan behaviour. Leave the defaults unless you know exactly what you are changing. The fans should never be switched off permanently or throttled heavily. Provide cool, dust-free intake air.

If temperatures stay high, the firmware is rarely the cause: lower the power target, check the intake air and clean heatsinks and fans.

Set up monitoring

The Braiins OS+ web interface shows hashrate, temperatures, fans and power draw per hashboard. Your pool's dashboard also shows the hashrate from the pool's point of view. If it differs clearly from the miner's display over several hours, check network and pool settings.

If you run several miners, you can keep an eye on them together with Braiins Toolbox. With our live calculator you can work out electricity costs for different power levels; earnings depend on the Bitcoin price and difficulty and cannot be guaranteed.

Braiins OS+ pre-installed: our service

If you want to skip the installation: for Antminer S19j Pro and S19k Pro units bought from us and shipped from stock, we deliver with Braiins OS+ pre-installed on request. On the product page you choose the Braiins variant under operating system.

This does not change the risks and notes above: the firmware is installed at your express request, and during checkout you confirm our mining software notice. The price of the pre-installation and any current promotion are shown on the product page.

Frequently asked questions about Braiins OS

• Is Braiins OS free? Braiins OS is open source. Braiins OS+ with autotuning charges a small developer fee; the current terms are on braiins.com. If you order the unit from us with Braiins OS+ pre-installed, the product page shows the price of the pre-installation.
• Do I lose the warranty with Braiins OS? For consumers the statutory warranty remains in place. There is no claim for damage demonstrably caused by mining software, overclocking or insufficient cooling. The details are in our mining software notice.
• Does Braiins OS+ run on the S19j Pro and the S19k Pro? Braiins OS+ versions exist for both models. Which one fits your unit depends on the control board and hardware version. Check the compatibility overview on braiins.com before downloading.
• Can I go back to the stock firmware? Braiins describes a way back to the stock firmware in its documentation. You need the matching Bitmain firmware file for your exact model and have to follow Braiins' current instructions.
• How do I find the IP address after installation? The IP may have changed after the restart. Check your router's device list or search for the miner on the network with Braiins Toolbox. A DHCP reservation in the router keeps the address stable afterwards.
• How do I limit power for PV operation or quieter running? Set a lower power target in watts in autotuning. Less power means less waste heat, and the fans usually have to work less. Start conservatively, watch temperatures and hashrate, and adjust the value step by step.
• Do I have to install Braiins OS+ myself? No. For S19j Pro and S19k Pro units bought from us, we deliver with Braiins OS+ pre-installed on request. On the product page you choose the Braiins variant under operating system.
• The miner is not reachable after installation. What now? Wait a few minutes, as the first start after installation takes longer. Then check the network cable and the LEDs on the LAN port, look for the new IP in the router or with Braiins Toolbox, and otherwise follow the troubleshooting in the Braiins documentation. For units from us, our WhatsApp support can help.

Facts about buying from Mining Technologies

• Dealer: Mining Technologies (owner: Arthur Reiz), Am Brauhaus 4, 91413 Neustadt an der Aisch, Germany · Since 2021 · over 2,000 miners sold · eBay: 100% positive, 238 items sold (as of 2026-10-15) · 5.0★ Google (43 reviews, as of 2026-10-15)
• Contact: Phone +49 179 4382414, WhatsApp on the same number, email info@miningtechnologies.info
• Shipping: S19j Pro and S19k Pro: free shipping in Germany · other devices under €1,000: €19.90 · free from €1,000 · EU (incl. Austria) €29.90 · free from €1,000 order value · EU islands €49.00 · Switzerland €40.00 (import duties are paid by the recipient)
• Delivery time: S19j Pro and S19k Pro: delivery within 48 hours (business days, Germany) after payment, EU 3–6 business days. Models from our HK warehouse: 10–14 days.
• Payment & warranty: Prepayment (bank transfer), PayPal, Apple Pay, Credit card (Mollie), Cryptocurrency (NOWPayments); invoice showing VAT; statutory warranty and 14-day right of withdrawal for consumers

See also:

• FAQ