I have a Monoprice Select Mini v2 and it came with a 256 MB SD card. I have a bunch of 16 GB cards. I have made sure that the new SD card has a FAT32 filesystem. I copy the gcode file onto this card and when I put it in the printer, it can't find any files!
And yes, the file is at the root level of the filesystem and it uses the proper naming convention. The file works on the old card.
Since the old card still works, this isn't an emergency, but I want to have a backup and I don't have any other cards that small.