Galaxy S3, rooted, ES File Explorer Pro, OTG adapter for SD card with USB socket. The OTG adapter works fine with SD cards formatted to FAT32. I have a freebie 250Mb flash drive which when plugged into phone via OTG adapter shows instantly in ES File Explorer. In Windows, it shows as formatted to 'FAT' (i.e. not FAT32 or ExFAT). Two other flash drives (formatted to FAT32), a 4Gb and an 8Gb, do not register at all. I have tried formatting one to 'FAT' (using the Windows CMD prompt), but it made no difference. No show. Any clues why, or what I should do? Advice welcomed!