MicroSD management in real storage mode

[robustini]

I was trying to transfer to the MicroSD installed on a SpeedyBee F405 WING Mini the database for the terrain, the file is about 30 Mb, via MavFtp with Mission Planner the transfer is eternal, I aborted it after a few minutes and had transferred only 1 Mb of 30, something unacceptable.
In many drones reaching the MicroSD inside the FC is a feat, let alone in the SpeedyBee F405 WING Mini which has three pcbs and the card is in the middle one, is not very smart to remove, so why don't implement the possibility to interface to that media in real storage mode?
INAV does and well too, with the same FC I transferred those 30 Mb at 355 Kb/sec, a whole different thing, that is in about 90 seconds, maybe in MavFtp it would have taken me half an hour or maybe longer.
The speeds are incomparable to having the MicroSD in the PC, but they are still bearable, with MavFtp they are not.
Obviously to create this storage mode INAV it performs a targeted reboot of the FC, and to return to normal mode just simply repower it.
So INAV after this targeted reboot treats the MicroSD as real storage, as if the MicroSD were inserted into a reader connected to the PC, with all the features obviously available, even formatting.
Can we implement this? It would be not useful but very useful, one could also download logs at incredible speeds, although actually it is not the download that is the real problem with MavFtp but the upload.

[robustini]

Now to perform an upload I have two alternatives:

1. save parameters, flash INAV, activate storage, perform upload, reflash Ardupilot, reload saved parameters
2. I disasseble the FC, take out the MicroSD, put it in the PC reader, perform the upload, reinstall the MicroSD in the FC, remount the FC

Acting on the hardware is not the top, and often involves having to reach the FC which in some drones means disassembling a whole bunch of things, it is easier then the first option but a third would be more useful:

3. I perform a special reboot with Ardupilot which treats the MicroSD with real storage, perform the upload at an acceptable speed, re-power the FC

Dedicated firmware to be flashed with Mission Planner would also be sufficient to perform quick operations on the MicroSD without having to go through INAV which is quite inconvenient.