For mobile emulation on Android devices, storage space is at an absolute premium. Both AetherSX2 and its community-maintained update, NetherSX2, fully support CHD ROMs. Converting your mobile PS2 library to CHD can easily free up dozens of gigabytes on your phone's internal storage or MicroSD card. A Note on Finding and Managing Pre-Converted CHD ROMs
The question of ROM legality is frequently misunderstood, so let me clarify. ps2 chd roms exclusive
As of 2024/2025, support is now widespread, but there is one major holdout. For mobile emulation on Android devices, storage space