Quote from: DaveF on April 21, 2019, 01:44:39 AM

You can always try to revert to an older firmware:

https://support.bitmain.com/hc/en-us/articles/360019493654-S9-series-S9-S9i-S9j-S9-Hydro-Control-Board-Program-Recovery

Standard disclaimer: If you are not sure what you are doing don't do it. If you mess it up and brick your miner don't yell at me. You are doing this at your own risk.

I don't really like that information offsite so I'll paste it here:

Quote from: Jocelyn

S9 series (S9, S9i, S9j, S9 Hydro) Control Board Program Recovery

This method applies to the following situations:

The miner is power-off in the upgrading process.
The miner cannot start (cannot find IP).
The miner can only use the default factory workers.

Tools required:

The MicroSD card recommended capacity of less than 16GB. Larger capacity MicroSD cards are not recommended as they are very susceptible to errors.
A computer running Windows XP or later
Card reader

Software required:

We use the same image as T9+. Download Link: https://service.bitmain.com/support/download

On the left sidebar click "Flashing SD Card With Image>>Tools and Instructions to Image SD Card. Scroll up to the page and find t9+-SD Tools.zip. Load t9+-SD Tools.zip to your computer in a convenient file location.

Flashing Instructions :

Remove control board from miner assembly.
Know your control board model and enable it to flash using the SD card. (See three types of control boards explanation below)
Insert MicroSD card into computer and format to FAT32.
Unzip the downloaded t9+-SD Tools.zip and copy the contents to the MicroSD card.
Insert the MicroSD card into the card slot on the control board
Power on the control board. Allow at least 90 seconds for the files to load automatically. When loaded, the red and green indicator lights on the control board will blink.
Power on the control board and access the miner interface. Go to the Upgrade page and Uncheck Keep Settings. Flash the firmware and run the miner for 20 minutes.

Note that there are three types of control boards and each of them requires a different way to enable flashing.

1. One complete board such as model CRT0401, CRT0402.
To enable it to flash using SD card, you need to shift the JP4 jumper to the right as shown below.

After flashing completed, power off the control board and shift the JP4 jumper back to the original position.

2. Double boards such as model CRT0302.
To enable it to flash using SD card, you need to shortcircuit the AB as shown in the picture below.

3. Boards without SD card slot such as model CRT0301
It doesn't support SD card flashing.

Possible solutions to solve the flashing failure

1. Reformat the TF and make sure you've copied the correct firmware.
2. Press the TF softly to ensure it's well attached.
3. Dust and clean the TF.
4. Try with another good known TF.

Note: TF card = MicroSD card. This was coined in China to avoid paying Sandisk...

BTW: Moving the JP4 jumper is the same method you can use to boot Braiins OS without flashing it into NAND (ie. for safely testing it).