QLn Series Firmware Download Failure and Force Download Mode | Zebra

QLn Series Firmware Download Failure and Force Download Mode

Article ID: 40647604




If the printer locks up while attempting to boot up or the unit is boot looping (starting up, shutting down, and then attempting to start up again) you will need to attempt forcing a firmware file to it.  This procedure can also be used for standard firmware upgrades if normal procedures fail

Applies To

Zebra QLn Series Mobile Printers

Cause or Overview

A corrupted firmware file can cause this issue to occur.  This issue was typically only seen with initial firmware releases for the product and has since been corrected in current firmware versions


 This Solution is useful when:

  • The standard procedure for downloading firmware fails


Force Download Procedure

You will need the following firmware and utilities for this USB-connected method.

  • You can download the ZDownloader Utility which is required for this procedure from the following link  Read More>>
  • You can download the firmware for your printer from the appropriate printer support page below:
    QLn220 Printers  Read More>>
    QLn320 Printers  Read More>>
    QLn420 Printers  Read More>>
  • The procedure below details how to appropriately send the firmware file to the printer:


1. Turn the printer off.

2. Unplug the battery.

3. Put a roll of paper or labels in the printer. 

4. Connect the USB cable (insure that the battery is NOT installed).

5. Install the battery.

6. Hold down the two soft keys at the corners of the display and then push the green power button while holding the two soft keys.

The printer will enter Forced Download Mode and the display will look as follows:

7. Open the ZDownloader, click on the file menu item "Printer" and select “Auto Detect”

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This message displays:

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Then this one. 

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8. Select the printer that shows USB as the Port.

9. Select "File", "Select Firmware File"

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10. Browse to the location of the saved firmware file and click "Open"

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11. From the top menu select "Printer", "Download All" 

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It will take a few minutes to download while the progress message displays.

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 The printer LCD will display the following starting with......

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The display will change as the download progresses

  • Saving Firmware to Flash  DO NOT Turn Off the Printer
  • Files Decompressing
  • Writing Files to Flash
  • Finishing Install


This message will be displayed when the printer completes the firmware installation.

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+ Product Codes

  • QLn Series Healthcare Mobile Printers
  • QLn Series Mobile Printers
  • QLn220 Healthcare
  • QLn220 Mobile Printer
  • QLn320 Healthcare
  • QLn320 Mobile Printer
  • QLn420 Mobile Printer