Create Recovery Disk for Intel-based Terastation

Get the necessary tools/resources
First, xtract the boot files for your device from the firmware using this method: Extract Boot Files from Stock Firmware

Using a linux system with grub2 and xorriso installed.

Create a grub.cfg suitable for your device:
Terastation WVHL/QVHL/6VHL/8VHL/RVHL set timeout=0 set default=0

set root='(hd0)'

menuentry "Terastation WVHL/QVHL/6VHL/8VHL/RVHL EM Mode" { linux /vmlinuz-atom_d510.buffalo root=sde1 rw usbboot=yes mode=initilize ts4000=no acc=no initrd /initrd-atom_d510.buffalo }

Terastation 4000 Series set timeout=0 set default=0

set root='(hd0)'

menuentry "Terastation 4000 Series EM Mode" { linux /vmlinuz-atom_usi.buffalo root=sde1 rw usbboot=yes mode=initilize ts4000=yes acc=no initrd /initrd-atom_usi.buffalo }

Terastation 5000 Series set timeout=0 set default=0

set root='(hd0)'

menuentry "Terastation 5000 Series EM Mode" { linux /vmlinuz-atom_d510.buffalo root=sde1 rw usbboot=yes mode=initilize ts4000=no acc=no initrd /initrd-atom_d510.buffalo }

Create a directory tree to create the disk image from:
mkdir -p disk/boot/grub/

Add the boot files and the grub config file:
disk/initrd-atom_d510.buffalo disk/vmlinuz-atom_d510.buffalo disk/boot/grub/grub.cfg

Generate the iso file
grub-mkrescue -o ts-recovery.iso disk/

Copy the image to a usb drive
dd if=ts-recovery.iso of=/dev/sdx bs=4k

The disk is now ready to use to boot the device into EM mode for firmware installation