That's the idea. Yes, CF cards are the safest bet for this, because they really are native PATA/IDE drives, which is what the empeg requires. CF Card "adapters" are totally passive devices, which simply expand the CF pin-out to the IDE-44 pin spacing, so compatibility of those has never been an issue.

SD cards, though cheap, don't seem to have compatible adapters available.

Roger does have a nicely working mSATA drive w/adapter in his empeg, but it is unknown if that was good fortune or if it is something easily repeated.

The builder_v21 is the best way to initialize any new "drive" for use in a Mk2/Mk2a empeg/RioCar. You'll still have to copy your tunes over afterward (direct copy, PC copy, rsync, emplode, jemplode etc..), but the builder sets everything up nicely for you before The Copy.

Note: At some point soon-ish, I hope to also provide just the builder_v21 root filesystem, with all of its goodies, as a non-destructive .upgrade for existing disks that are already loaded with tunes/playlists.

Cheers