For sdcard, on this board it doesn’t support 1.8v io mode for hs200/400 speed mode…
For emmc, some software work need to be done to enable 1.8v supply for it.
(Thanks to neggles from Pine64 community to find out this)
Edit: current discovery is based on v1.2A board schematic, since there are some big changes on v1.3B pcb, we might need to check that version of schematic to confirm if this design problem still exists.