Currently the script uses blockdev --getpbsz to detect the physical block size. However, this is incorrect for Advanced Format drives using SCSI-to-ATA Translation (SAT; includes USB enclosures and such), as detailed here: http://nunix.fr/index.php/linux/7-astuces/65-too-hard-to-be-above-2tb

The correct way to determine it is by using either hdparm -I or smartctl -d sat -a. Since the former doesn't need explicit specification that it's a SAT drive, it's probably better to use that, like so:

BLOCK_SIZE=$(sudo hdparm -I /dev/$DEVICE| grep "Physical Sector size"| awk '{print $(NF-1)}')