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Restoring Antminer S19 (76 chips) from an SD card

This guide explains how to restore Bitmain stock firmware from an SD card on an Antminer S19 (76 chips per board, Xilinx control board) if a device running EMCD firmware has stopped booting or working.

1. When to use this

Restoring from an SD card is a last resort: it erases all device settings and requires physical access to the miner. Try simpler methods first.

Situation

What to do

The device doesn't appear on the network after installation or an update

Follow the steps in section 9 of the FW Flasher guide: wait 10 minutes, check whether the address has changed, and power-cycle the device once. If that doesn't help, restore from an SD card

An error at stage F or W in FW Flasher, the retry also failed, and the device doesn't boot after rebooting

Restore from an SD card

The web interface opens, but the miner isn't mining, settings are "broken", or the password is forgotten

Not an SD card case. Reset the settings: hold the button on the case for 5 seconds, or use Restore factory settings in the web interface

You need to install a different version of EMCD firmware

Not an SD card case. Update via the web interface or FW Flasher

You want to go back to Bitmain stock firmware

Restore from an SD card

The device reboots constantly, the LEDs behave strangely, or it keeps appearing and disappearing on the network

Restore from an SD card

The button on the case and the reset in the web interface don't restore the stock firmware: they only reset EMCD firmware settings.

Supported hardware. The recovery kit is only for Antminer S19 with 76 chips per board (Xilinx control board). EMCD firmware installs only on this model, so any miner that has or had it installed is compatible. This kit must not be used for other models (S19j, S19 Pro, S19 XP, S21, etc.): the model is checked before writing, and the device will show an error (red indicator).

2. What the procedure does

A Bitmain service system boots from the SD card. It verifies the file signatures and rewrites the control board's internal memory: the bootloader, kernel, system, and miner firmware. No network or pool is required for this.

What

Result

Firmware

Bitmain stock firmware for Antminer S19 (build of June 1, 2020)

Pools and workers

Erased: there are no pools, and the miner won't mine until you set them

Network settings

Erased: the address is assigned automatically (DHCP). If a static IP was used, the address will change

Web interface username and password

Reset to factory defaults: root / root

Tuned chip parameters (EMCD)

Erased; they're tuned again after EMCD firmware is reinstalled

MAC address

Preserved

Before restoring, prepare the information listed in section 3: you'll use it to restore operation after reinstalling EMCD firmware.

3. Preparation: what you'll need

Hardware:

  • An SD card from 1 to 16 GB (microSD with an adapter or full-size, depending on the slot on the control board). Cards larger than 16 GB and SDXC cards (64 GB and above) aren't recommended: the board may not recognize them.

  • A computer with a card reader (Windows, macOS, or Linux).

  • Physical access to the miner: you'll need to insert the card into the slot on the control board and turn the power on and off.

Files:

  • The recovery archive S19-recovery-xil-06.2020.zip

    • This is Bitmain's official kit for Antminer S19 on a Xilinx control board (stock firmware of June 1, 2020).

  • Archive checksum (SHA-256):
    ​52d5855e06780f7da84d89cf36cbd6de9ad128a9fc2f7e589c44c26e6898f16e

    • To verify it:

      • Windows: certutil -hashfile S19-recovery-xil-06.2020.zip SHA256,

      • macOS: shasum -a 256 S19-recovery-xil-06.2020.zip,

      • Linux: sha256sum S19-recovery-xil-06.2020.zip.

      • If the checksum doesn't match, the archive is corrupted: download it again.

After unpacking, the archive contains:

File or folder

Purpose

bin/update.bmu

Stock firmware that is written to the board

uImage, devicetree.dtb, uramdisk.image.gz, update.image.gz

Service system that boots from the card

miner.btm

Bitmain service file

*.sig

File signatures

readme.factory

File checksums

Copy all files to the card as is; nothing needs to be deleted.

Your information (write it down before you start, as it won't be on the device after recovery):

  • the miner's IP address, and if it's set manually, the subnet mask, gateway, and DNS;

  • pool addresses, worker names, and their passwords;

  • the device name (hostname), if you changed it;

  • if the device still opens in a browser, the EMCD firmware version from the System section.

4. Preparing the SD card

  1. Insert the card into your computer.

  2. Format it as FAT32 (called "FAT" in some programs):

    • Windows: right-click the card in "This PC" → "Format" → file system FAT32 → "Start". If FAT32 isn't in the list, use the free SD Card Formatter tool from the SD Association.

    • macOS: "Disk Utility" → select the card (the whole device, not a partition) → "Erase" → format MS-DOS (FAT), scheme Master Boot Record (MBR).

    • Linux: create an MBR partition table with a single partition on the card and format it: mkfs.vfat -F 32 /dev/sdX1.

    Important: the file system must be on the first partition of the card. Standard formatting of a new card does exactly that. Image writing tools (balenaEtcher, Win32DiskImager, Rufus) aren't needed: the files are copied to the card as regular files.

  3. Unpack the recovery archive on your computer.

  4. Copy the contents of the archive to the root of the card, not into a separate folder. After copying, the root of the card should contain uImage, devicetree.dtb, uramdisk.image.gz, update.image.gz, miner.btm, the .sig files, and the bin folder with update.bmu inside.
    ​
    ​Correct:

    SD-карта (E:)

    ├── bin

    │ └── update.bmu

    ├── devicetree.dtb

    ├── devicetree.dtb.sig

    ├── miner.btm

    ├── miner.btm.sig

    ├── uImage

    ├── uImage.sig

    ├── update.image.gz

    ├── update.image.gz.sig

    └── uramdisk.image.gz

    Incorrect: E:\S19-recovery-xil-06.2020\uImage, with the files inside a folder named after the archive.

  5. Safely eject the card ("Eject" in Windows, the eject button in macOS).

5. Recovery

Warning. Do not turn off the miner's power or remove the SD card while writing is in progress. The procedure also rewrites the control board's bootloader. If writing is interrupted, the board may stop booting entirely, and it can only be restored at a service center.

  1. Turn off the miner: disconnect power to the power supply unit.

  2. Insert the SD card into the slot on the control board. You don't need to disconnect the network cable or the hashboards.

  3. Turn on the power.

  4. Wait. The board will boot from the card and start writing. This usually takes a few minutes; allow the procedure at least 5 minutes. During writing, the indicators may be off or blinking. This is normal. The fans may run louder than usual.

  5. Check the indicators on the miner's front panel:

Indicator

What it means

What to do

Green is solid, red is off

Recovery completed successfully

Go to step 6

Red is solid, green is off

Error: the files failed verification, the card couldn't be read, or the kit isn't for this model

See "If it didn't work"

After 10 minutes, neither is solid

The board didn't boot from the card

See "If it didn't work"

6. Turn off the miner and remove the SD card.
Be sure to remove the card: while it's inserted, the miner will restart recovery every time it's powered on and won't start working.

7. Turn on the miner without the card. It will boot with Bitmain stock firmware. The first start usually takes 2–5 minutes.

6. After recovery

Finding the device on the network

The address is assigned automatically (DHCP) and may differ from the previous one. You can find the device in any of these ways:

  • FW Flasher: scan your farm's address range. The device will appear with stock firmware and the "supported" status.

  • DHCP client list on your router: search by the miner's MAC address (it doesn't change) or by the name Antminer.

You can open the web interface at the address you found; the username and password are root / root.

Reinstalling EMCD firmware

The device now runs Bitmain stock firmware, so EMCD firmware is installed as for a first installation: only via FW Flasher (it can't be installed through the stock firmware's web interface). For the steps, see the guide "Installing EMCD Firmware Using Antminer FW Flasher".

Pay attention to the pool selection in FW Flasher: there are no pools on the device after recovery, so the "transfer pools from stock firmware" option will transfer an empty list. Either choose to switch to the EMCD pool, or specify the pools in the web interface after installation using the information from section 3.

After installation:

  1. If the device had a static IP, set it again in the network settings.

  2. Check the pools and workers.

  3. If you previously used a web interface password other than root, set it again.

  4. Give the firmware time to tune the chip parameters: right after installation, the hashrate may be below target.

If you want to stay on Bitmain stock firmware, simply specify the pools in the stock firmware's web interface.

7. If it didn't work

Symptom

Possible cause

What to do

Red indicator

The files were corrupted during download or copying

Download the archive again, reformat the card, and copy the files again

Red indicator

The card couldn't be read: wrong file system or no partition table

Reformat the card as FAT32 following section 4 (MBR partitioning, a single partition)

Red indicator

A different miner model (not an S19 with 76 chips)

Check the model on the label on the case. This kit isn't suitable for other models: escalate

Neither indicator is solid, and the device behaves as usual (or as it did before recovery)

The board didn't detect the card: files are in a subfolder, the card is too large, or there's a poor contact

Check that the files are in the root of the card. Blow the dust out of the slot. Try a different card of up to 16 GB

Green indicator, but after powering on without the card the device doesn't appear on the network

The address has changed, or the device is still booting

Wait 10 minutes, then search by MAC address in the DHCP list or by scanning in FW Flasher. Check the network cable

After powering on without the card, the green indicator lights up again and the device doesn't work

The card wasn't removed, or another card with the same files is inserted

Turn off, remove the card, turn on

No attempt helped

Control board malfunction

Escalate (section 8). A service center may be required

If the first attempt ended with an error, you can repeat the recovery: turn off the miner, fix the cause, insert the card again, and turn it on.

8. Escalation

Provide the following to EMCD support, and support will pass it on to the firmware developers:

  • the model from the label on the case and the serial number;

  • what happened before the problem: installation via FW Flasher (at which stage the error appeared in the "Progress" column), an update via the web interface, a power outage, etc.;

  • the EMCD firmware version, if known;

  • what the indicators showed during recovery (which color, after how many minutes);

  • which cards you tried (capacity, type) and how you formatted them;

  • if possible, a photo of the control board with the SD card slot.

Quick reference

Restoring Antminer S19 from an SD card:

  1. Write down the miner's settings: pools, workers, IP address (if set manually). They'll be reset after recovery.

  2. Take an SD card of up to 16 GB and format it as FAT32.

  3. Unpack the archive and copy its contents to the root of the card (the bin folder and the uImage, devicetree.dtb, and other files must be directly on the card, not in a nested folder).

  4. Turn off the miner, insert the card into the slot on the control board, and turn the miner on.

  5. Wait 5–10 minutes. Don't turn off the miner or remove the card while writing is in progress.

  6. If the green indicator lights up, turn off the miner, remove the card, and turn it on again. If the red indicator is on, contact us.

  7. The miner will boot with Bitmain stock firmware, obtain an address automatically, and use the username and password root / root. EMCD firmware can be reinstalled via FW Flasher.

How do I contact support?

If you have any questions about the firmware, update files, or recovery, contact EMCD Mining support:

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