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Antminer S21 & T21 firmware — free download

Free AsicMiner firmware for the Antminer S21, S21 Pro, S21 XP, S21+ (air, hydro and immersion) and T21: guided autotuning, per-board monitoring and a clean rollback path. Pick the build for your control board below.

Download firmware How to install
12 model families on this page
53 install & update packages
v1.3.3 latest version line
  • Up to +20% hashrate
  • Up to −25% power
  • Live monitoring & autotuning
  • Free & reversible

Choose your Antminer S21 / T21 build

Every package is tied to a specific control board and storage target — match both before flashing. Not sure which control board you have? →

Antminer S21 Firmware

Firmware packages for Antminer S21.

4 packages
Fits Antminer S21 151T Antminer S21 175T Antminer S21 188T Antminer S21 195T Antminer S21 200T
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.56 MB Update 15.53 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.61 MB Update 12.58 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.31 MB Update 12.28 MB
v1.2.6 Stable Amlogic SD card
Install 39.71 MB Update 18.25 MB

Antminer S21 Hydro Firmware

Firmware packages for Antminer S21 Hydro.

4 packages
Version Status Controller Storage Download
v1.3.3 Stable Xilinx NAND / internal flash
Install 15.44 MB Update 15.44 MB
v1.2.7 Stable Xilinx NAND / internal flash
Install 12.57 MB Update 12.58 MB
v1.2.6 Stable Xilinx NAND / internal flash
Install 12.27 MB Update 12.27 MB
v1.2.6 Stable Xilinx SD card
Install 16.25 MB Update 12.35 MB

Antminer S21 Immersion Firmware

Firmware packages for Antminer S21 Immersion.

4 packages
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.56 MB Update 15.53 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.61 MB Update 12.58 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.30 MB Update 12.27 MB
v1.2.6 Stable Amlogic SD card
Install 39.70 MB Update 18.23 MB

Antminer S21 Plus Firmware

Firmware packages for Antminer S21 Plus.

4 packages
Fits Antminer S21+ 216T Antminer S21+ 225T Antminer S21+ 235T
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.56 MB Update 15.53 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.61 MB Update 12.58 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.29 MB Update 12.26 MB
v1.2.6 Stable Amlogic SD card
Install 39.72 MB Update 18.25 MB

Antminer S21 Plus Hydro Firmware

Firmware packages for Antminer S21 Plus Hydro.

6 packages
Version Status Controller Storage Download
v1.3.3 Stable CVitek NAND / internal flash
Install 11.81 MB Update 11.82 MB
v1.3.3 Stable Xilinx NAND / internal flash
Install 15.45 MB Update 15.46 MB
v1.2.7 Stable CVitek NAND / internal flash
Install 8.94 MB Update 8.95 MB
v1.2.7 Stable Xilinx NAND / internal flash
Install 12.56 MB Update 12.57 MB
v1.2.6 Stable Xilinx NAND / internal flash
Install 12.25 MB Update 12.26 MB
v1.2.6 Stable Xilinx SD card
Install 16.25 MB Update 12.35 MB

Antminer S21 Pro Firmware

Firmware packages for Antminer S21 Pro.

4 packages
Fits Antminer S21 Pro 220T Antminer S21 Pro 234T Antminer S21 Pro 245T
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.56 MB Update 15.53 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.62 MB Update 12.59 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.30 MB Update 12.26 MB
v1.2.6 Stable Amlogic SD card
Install 39.71 MB Update 18.24 MB

Antminer S21 XP Firmware

Firmware packages for Antminer S21 XP.

4 packages
Fits Antminer S21 XP 270T
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.57 MB Update 15.54 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.61 MB Update 12.58 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.30 MB Update 12.27 MB
v1.2.6 Stable Amlogic SD card
Install 39.70 MB Update 18.24 MB

Antminer S21 XP Hydro Firmware

Firmware packages for Antminer S21 XP Hydro.

4 packages
Fits Antminer S21 XP HYD 473T
Version Status Controller Storage Download
v1.3.3 Stable Xilinx NAND / internal flash
Install 15.44 MB Update 15.44 MB
v1.2.7 Stable Xilinx NAND / internal flash
Install 12.57 MB Update 12.58 MB
v1.2.6 Stable Xilinx NAND / internal flash
Install 12.25 MB Update 12.26 MB
v1.2.6 Stable Xilinx SD card
Install 16.24 MB Update 12.34 MB

Antminer S21 XP Immersion Firmware

Firmware packages for Antminer S21 XP Immersion.

4 packages
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.57 MB Update 15.54 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.62 MB Update 12.59 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.29 MB Update 12.26 MB
v1.2.6 Stable Amlogic SD card
Install 39.71 MB Update 18.24 MB

Antminer S21e Hydro Firmware

Firmware packages for Antminer S21e Hydro.

2 packages
Fits Antminer S21 E HYD 228T
Version Status Controller Storage Download
v1.3.3 Stable Xilinx NAND / internal flash
Install 15.45 MB Update 15.45 MB
v1.2.7 Stable Xilinx NAND / internal flash
Install 12.57 MB Update 12.57 MB

Antminer T21 Firmware

Firmware packages for Antminer T21.

11 packages
Fits Antminer T21 180T Antminer T21 190T
Version Status Controller Storage Download
v1.3.3 Stable Amlogic NAND / internal flash
Install 20.56 MB Update 15.53 MB
v1.3.3 Stable CVitek NAND / internal flash
Install 11.81 MB Update 11.82 MB
v1.3.3 Stable Xilinx NAND / internal flash
Install 15.44 MB Update 15.45 MB
v1.2.7 Stable Amlogic NAND / internal flash
Install 17.61 MB Update 12.58 MB
v1.2.7 Stable CVitek NAND / internal flash
Install 8.94 MB Update 8.95 MB
v1.2.7 Stable Xilinx NAND / internal flash
Install 12.59 MB Update 12.59 MB
v1.2.6 Stable Amlogic NAND / internal flash
Install 17.31 MB Update 12.28 MB
v1.2.6 Stable Amlogic SD card
Install 39.71 MB Update 18.24 MB
v1.2.6 Stable CVitek NAND / internal flash
Install 8.62 MB Update 8.63 MB
v1.2.6 Stable Xilinx NAND / internal flash
Install 12.24 MB Update 12.25 MB
v1.2.6 Stable Xilinx SD card
Install 16.25 MB Update 12.35 MB

Antminer U3s21exph Firmware

Firmware packages for Antminer U3s21exph.

2 packages
Version Status Controller Storage Download
v1.3.3 Stable Xilinx NAND / internal flash
Install 15.43 MB Update 15.44 MB
v1.2.7 Stable Xilinx NAND / internal flash
Install 12.57 MB Update 12.57 MB

Install in three steps

From download to a tuned miner — usually under 15 minutes.

  1. 1

    Pick your build above

    Match your exact model, control board and storage type.

  2. 2

    Flash the package

    Install fresh or update in place — the guide covers both paths.

  3. 3

    Pick a profile & tune

    Efficiency, balanced or max output — autotune does the rest.

Read the full install guide

Antminer S21 / T21 firmware — frequently asked

Is the Antminer S21 / T21 firmware really free?
Yes — every package is free to download. The firmware runs a small, transparent dev fee on hashrate, in line with the rest of the industry.
Which Antminer S21 / T21 models are supported?
Every model family listed on this page has verified install and update packages. Open a family to see the exact builds for your control board and storage type.
How do I know which control board my miner has?
Open the miner and check the controller module label, or follow the identification steps in our installation guide — Amlogic, BeagleBone, CVitek and Xilinx boards each have a matching package.
Can I go back to stock firmware?
Yes. Installation is staged with power-limit protection and every model keeps a documented rollback path — you can return to a previous build at any time.

Looking for another model?

Antminer S19, T19 Antminer L9 Antminer L7 All models & filters →

Need a hand flashing your Antminer S21 / T21?

Our engineers install and tune remotely or guide you step by step — free for firmware users.

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