Kenwood DNX7250DAB new map help

Hi I'm new here

I recently bought a DNX7250DAB from eBay, I manage to update the software/firmware but no new updates for maps

So I bought a sd card loaded with new maps from eBay and was told this will work fine in my unit, I ended up getting a download link so didn't have to wait for delivery
Bought a 32gb SD card and put files on but no new maps show in the installed map section on my unit?
I have read I can manually update certain files by linking to laptop, I hav bought a usb to usb male and link it to the female usb socket which is normally used for usb stick for music or videos then into my laptop but nothing shows up on laptop? I've downloaded garmin usb drivers but nothing?

Any help to either get my SD card working on unit or get my laptop to see the device as mass storage so can look at files?

I have ordered a 16gb SD card which is coming today and going to try with that incase 32gb is too much for unit

Thanks

Any success with 16gb? Also, was it from the Kenwood site you updated the firmware?