85 System Boot Menu

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Do this at your own risk

Do this entirely at your own risk. Unlikely, but potentially you could stop the system from starting up.


I found this description on the Internet. The option to roll back the software worked for me, but the option to install an image from the SD card, did not - it just installed v5.90 - I suspect that the signed version of the software is encrypted.

  • Copy any files from your Zumo that you need - eg Track Logs. This process may wipe out anything that you added.
  • Locate the Firmware that you want to install. Garmin Express puts a copy onto your computer.

For PC this is probably in the Garmin Express Data Directory:


C:\ProgramData\Garmin\CoreService\Downloads\PrimaryFirmware

So for the 2.90 firmware this would be in


C:\ProgramData\Garmin\CoreService\Downloads\PrimaryFirmware\PrimaryFirmware_PrimaryFirmware.006-B3484-00.6.60\gsup\006-B3484-00\6.60\full\rel\( long number )\B348400.update


The firmware file will be called B348400.update.


Mine was called B348400.update.signed. It didn’t work, so I renamed it B348400.update. It didn’t object to that, but it didn’t install 2.90 either.


Note that the actual location may vary from the one quoted above. Follow the similar path from C:\ProgramData\Garmin\CoreService\Downloads\.....
  • Put the firmware file onto an SD card in the \Garmin folder and insert the SD card into the Zumo XT
  • Switch off the Zumo XT - ie hold in the power button until the screen shows the Red Off Button, and press that.
  • Hold in the power button for a couple of seconds. Release and immediately press it again and hold it in - until ….
  • …. the logo appears, let go of the button and immediately press it again



  • A rather dim screen appears. Use the power button to cycle through the menu.
  • Select A03 Recover from Software Failure
  • Press and hold the power button until the menu changes to this one - I made this facsimile of it as it is extremely awkward trying to get a decent photograph of the dim screen with the reflections.


Option B02 - To install the software from the memory card

Option B03 - To reinstate the previous version of the software. You don’t need the copy on the memory card. Select Roll Back Software.

  • In either case, hold in the power button until things start to happen.
  • Update process starts - takes less than 5 minutes
  • The device starts automatically and greets you with the software selection.

B03 Rollback worked fine for me.


B02 install from the SD card I had no success with although the process seemed to work fine.


(But I had to rename the file from B348400.update.signed - which may have been the issue.

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The information on these pages has been acquired from personal experience of using and testing the behaviour of Basecamp and my Zumo XT. I have no links with Garmin, and these pages should not be regarded as instructions. They are presented for interest only. The contents of these pages must not be shared, copied, transmitted, redistributed or re-published in any form without my permission. (C) JHeath 2021.