I have nano pi neo core board, it has the uSD-card connector on its board. I need to connect another uSD-card to the board's interface, there're SPI interfaces I may try, but what to do with card detect - is there any way to tune driver and/or hardware configuration to use specific GPIO for card detect?
Thanks!
I'll assume you are already using the USB port but for what?
Do SD-cards have USB interface? The storage device must be secured inside the device (but at the same time be removable). Well, maybe there's another choice of having a kind of M2 disk, but I suspect cost of this disk will be comparable to the cost of the processor module 
I am open for suggestions, and thanks again.