Emufile - Drive is not controlled by the primary Nextor kernel

[zomgugoff]

I'm using MegaFlashRom SCC+ SD on a Yellow MSX for RC2014. The Yellow MSX boots a ROM with a Nextor. When trying to do anything with emufile, it reports that the drive (SD card in MFR) is not controlled by the primary Nextor kernel. I can neither create .emu files, nor set ones I created when not using the MFR.

Is there a way to get around this requirement?