darrin,
did you ever find a solution to this trouble you were having??
I had exactly the same problem, but managed to partially solve it by making sure the SCSI card reader was ID 0. (I have a CD-ROM at ID 1 and a hard drive at ID 2).
It is still not perfect, I have to boot the system with the flash card I want to use inserted, and I cannot change the card unless I reboot, but it's better than nothing!
Incidentally, my warpdrive.device version is 40.66