Is it possible?
We may copy DFU (or some bin) file to SD and while device started, it’s print “found new firmware on SD, upgrade?”
Bootloader must contains MSD subsystem and FAT.
What do you think about it?
Sorry my English ))
Yes, it is possible to make it work. Indeed, the Quad does something like this. However, Nano users would need, at least once, to use the old method to bring this new firmware updater onto their Nano, which means they will already have the needed tools (computer program for flashing firmware, USB cable). So I don’t think it brings so much advantage.