Using FAT Filesystem on the Macronix memory on the nRF9160-DK

[[email protected]]

Is there sample code to use a FAT Filesystem on the Macronix memory on the nRF9160-DK?
The full_modem_update sample uses the Flash but not as a filesystem.

It would be great to have a sample or even for mounting it.
Do I need a device tree overlay?
What is required in the mount data structures for the flash and the

Also, if our requirements for persistent storage change, it would be great to use the SD.
In addition to populating the SD socket, what is required?
It appears from the DevZone others have made it work but none of the posts offers a complete solution.

[[email protected]]

I think there is a misunderstanding of what we are trying to accomplish.
My goal was to use the new 1MB flash (U37) on the nRF9160-DK.
I am told it was added to the nRF9160-DK in January to allow for Full MODEM Update.
It is connected to spi3.
The samples/nrf9160/http_update/full_modem_updat
uses the SPI flash in serial mode to download the MODEM firmware then program the MODEM.
The code uses the 1MB flash in serial mode with no filesystem.

We want to use the 1MB SPI flash to store a FAT FS.
We can delete the FAT FS on the rare occasions when we need a full MODEM firmware update.
We need to use this from the "application processor."