Michael McMaster (SCSI2SD Developer);

"I believe I have tracked down the change which causes EMAX issues.  For the EMAX I originally needed to wait 100 microseconds between each SCSI phase change. Then I did work to support old XEBEC SASI controllers for the 4.8.1 firmware and this time was changed back to 10 microseconds."

The attached ZIP file contains a firmware for SCSI2SD V 5.1 that is used in an EMAX only. 
This resolves the previous 10ms timing issue.  In future versions of the SCSI2SD Util, Michael has stated