The PiSCSI/RaSCSI board for the Raspberry Pi supports virtual SCSI devices like hard disks or CD-ROM drives based on image files. From the Atari's perspective a SCSI drive is connected, but in fact the Atari reads/writes data from/to files located on the Raspberry Pi. Unless the device type is explicitly specified the emulation derives the type from the image file extension. For the Atari the extensions hds for regular hard disk drives and hdr for removable media drives are the best choice.
By SCSI2Pi devices files (/dev/*) as image files are directly supported, e.g.
For the Atari the respective SCSI device appears to be a physical SCSI memory card reader. There are no byte swapping issues when exchanging data with other platforms. Thus when partitioning with HDDRUTIL do not enable the respective option.