The RG552 has two SD Card Slots on the bottom.
TF1/INT on the bottom left.
TF2/EXT on the bottom right.
TF1/INT is used to boot Linux. When the SD card is removed the RG552 fresh boots off Internal Android 11.
This means Slot1 SD Card won't be visible in Android. (Note from what I've read after you see android boot screen you can push it back in and have access. Still doesn't seem practical.) (Wondering if possible to set something in file to avoid this?)
AmberElec Creates small FAT32 2GB partition for OS. Remaining space is games on exFat partition with remaining space.
Still this games partition in TF1 will only be read if TF2 is empty. It does in fact work.
So TF2/EXT should be used for android Roms.
When booting off Linux if SD Card 2 is detect that will be used for games.
So all games should be on sd Card 2.
Use exFat (NOT fat32) on new games sd card to avoid file size limitations.
exFat should be readable from android.