Onyx Boox Poke5P User Manual page 53

OTG External Flash Drives
This device supports Type-C
OTG flash drives. After a flash
drive is inserted, the flash drive
will be automatically recognized and loaded as a storage.
OTG devices require a power supply and will increase
battery consumption
Low storage warning
Please make sure of leaving at least 300MB of storage for
normal system running and relevant data storage. When
the storage is lower than 300MB, the system bar will show
a warning icon for "insufficient storage".