Originally asked at Lenovo forums because I've only ever witnessed this weird behaviour on my newly-acquired ThinkPad T480. But possibly something wrong with the OS instead of hardware.
I had for years previously been using Microsoft Surface Pro 4, with a micro-SD card slot that can be coveniently named A: to make it look like a floppy drive.
Now as I transition to the ThinkPad T480, I slot in the SD card and named it A: as well. But everytime I restart the whole system, the Windows in this laptop totally forgets the assignment and names it D: If I try another letter like E: it still reverts to D: on reboot.
Is there something wrong with this copy of Windows 10, or something about the communication between BIOS and OS that got lost in translation that the SD card slot in the laptop is indeed the same?
I tested plugging in a USB hard disk, named it D: while the SD card gets E: on reboot, the SD card becomes D: while the hard drive is forced to E: There seems to be some sort of "sorting order" happening in hardware that Windows cannot keep track of?