Oh, Android used to have an issue with the number of files it could index. (Archos made a 500GB Android player, and my mate filled it with tens of thousands of medium bitrate mono audio files he'd ripped from vinyl and recordings of 1960s pirate radio). This issue has probably been fixed now, and if you want the large capacity for fewer, high bit rate files you probably won't encounter it anyway.
The cheaper FiiO players use their own Linux variant, the pricier ones a custom Android. Reviews suggest that they play nice with Fat32 and exFAT SD cards.
Biting the hand that feeds IT
