Uh, if it has no internal memory, where do we put Rockbox?
Good question. Here is what the User Manual PDF previous linked to states with respect internal memory:
"Please note: The player DO NOT has internal memory.
Before using this player, please prepare a Micro SD card with music files at first."
SpecificationsMusic formats: AAC/AIF(AIFF)/APPLE Lossless APE/FLAC/OGG/MP3 /WAVE/WMA/WMA Lossless M4A/DSF/DSDIFF
Screen: 1.8" LCD screen
Size: 85.6×40.2×10.08mm
Capacity: No internal memory, support up to 256 GB micro SD card(SD card not included)Playing: 40 hours music playing at medium volume by earphone
Charging: 2 hours capacity Built-in 600mAh lithium
SNR: -94DB
Lyric format: LRC