Kenwood DNX7260BT Software Update Problem

[jimyol]

I'm having some difficulties in updating the software on my DNX7260BT and would appreciate some advice please. Perhaps the problem is my lack of understanding which isn't helped much by the poor instructions provided with the unit and on the Kenwood and Garmin sites.
I've updated the system software using the Kenwood website and now have the latest version V1.6.0.
The bluetooth module version is showing as version 3.12.0. The navigation software icon on the Kenwood site leads me to the Garmin website which invites me to download software version 4.20. My first question is "Is this the software update that I need", i.e. is this software on the Garmin site the update that I need for the software identified as Bluetooth Module on my headunit?
If that is the case, then why doesn't it update when I follow the download and update instructions. Basically, I'm following the instructions on the Garmin site, downloading, unzipping to a GARMIN folder on an SD card, inserting in the SD slot and nothing happens. I've tried loads of variations including capitalisation of the folder name, making sure the headunit is on navigation etc
Any suggestions appreciated
Jim

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