USB Recovery System for :fabrik / :vier

USB Recovery System | Back to Factory Defaults

If you have reached a point where KLANG:fabrik or KLANG:vier are not accessible from the network or the unit does not boot properly, there is a way to reinstall the KLANG operating system by a USB recovery procedure.

In case you have been redirected via KLANG:app to this page, please check via KLANG:app or if available the touch display of KLANG:fabrik if your serial number is KFZNOSER or K4zNOSER. If that is the case, please get directly in contact with our support team and include your serial number in the email –

PLEASE NOTE: settings, presets and log files will be lost and the unit will be reset to factory settings. ALL DATA WILL BE LOST.

Only proceed, if you are sure that it is a problem of the KLANG unit itself and not network connection problem. Only proceed if you want to DELETE all files and convert the unit to factory default settings!

What you need:

  1. KLANG USB Stick (empty, FAT formatted, must be working properly with KLANG unit)
  2. Mac or PC with USB port
  3. KLANG:fabrik / KLANG:vier, power cord connected, NO FURTHER xlr cables, network cables, etc connected.
  4. Recovery ZIP Archive –  Download KOS Recovery 4.3.19 files

If required, you can find the older KOS Legacy Recovery 2.0.4 here

Video instructions:

Step-by-Step instructions:

1. Format the USB Drive

Insert a USB drive into your computer and follow the steps in this link to format the drive properly. This step is required for the recovery procedure to start.

2. Unzip the Recovery ZIP Archive on your PC or MAC.

The current KOS recovery contains 5 files.

The KOS legacy recovery 2.0.4 looks like this (only 4 files, longer file names)



3. Copy Recovery Files to USB drive

Copy the 5 files to the top directory (root) of your empty, freshly formatted and partioned USB drive.


4. Insert USB drive

Make sure KLANG:fabrik / KLANG:vier is switched off. Disconnect ALL cables except for the power cord. Insert the USB drive containing the Recovery OS.

5. Initiate USB Recovery Routine

  • For KLANG:fabrik: Power on unit WHILE constantly MOVING one finger on the touch display until the display flashes black/white.
  • For KLANG:vier: Power on unit WHILE pushing and holding the button aside to the SUB-D connector in the back of the unit with a pen.

6. Wait for the Recovery to finish.

On KLANG:fabrik you can monitor the progress on the display. On KLANG:vier, depending on the version of the OS and Recovery version you might not see any LED light signals. In this case wait 10 minutes. You can also see the KLANG:vier LED through the ventilation grid on the left.

The recovery proceedure is finished when the normal booting screen is shown on KLANG:fabrik or the LED turns steady purple on KLANG:vier.

Now the device has booted successfully and is running in the Recovery OS. Install the current firmware according to the Firmware Update Guide.

KLANG:vier –
LED color codes

Normal Operation:
Red: Boot Stage 1
White: Boot Stage 2
Orange: Boot Stage 3
Purple: Operational -> OK!
Yellow: Error
During KOS Firmware Update:
Orange: Stage 1/4 or Stage 2/4
Yellow: Stage 3/4
White: Stage 4/4
Blue: Done, Switch Power OFF

During KOS Firmware RECOVERY:
red / green alternating: push-button press detected
Orange blinking @1sec: copying data from USB
short red / green alternating: beginning to read new file (4 total) – then proceeds with Orange

When file copy is finished KLANG:vier will restart 3 times automatically with the usual color code for normal operation and end up in purple.

Proceed to Update KOS to newer versions…

In case you want to directly update to a newer version just additionally copy the regular KOS update files to the recovery files. During the first reboot after the recovery is completed the KOS update will start immediately.

You think that you don’t need to apply the USB Recovery procedure? Or you find out that the KOS version after the recovery is not the latest version you want to use?

Read more here on how to update the KOS to the latest version.

blog - firmware update-01

Free and Open Source Software Declaration: This product contains free and open source software. For licensing information please click here…

We hope that you find this article helpful. Please let us know, if you have any problems or questions–