The fastata acts like the onboard controller when the driver isnt running.
So if you boot with no startup-sequence the driver wont load and it will allow you to use the cfcard as if it was connected straight into the onboard ide controller.
You can then go to the s folder and use something like ed to edit the startup-sequence and rem out the ata3.prefs line exit ed and it will ask you to save the file.
Reboot and it will boot straight into Workbench as if it was connected to the onboard ide.
Very weird you couldnt access the cfcard when booting without a startup-sequence.