During the boot process, the POA fails to load with error message 'SGM409: Fatal Error'.
First seen in
Sophos Disk Encryption
SafeGuard Device Encryption
This error occurs when there is a SATA Raid Controller installed, the POA fails to load successfully.
What To Do
Depending on manufacturers implementation in the BIOS, you may need to change the S-ATA controller settings to a "compatibility" or "combined" mode manually in the BIOS or trying the Shift+F6 POA hotkey to switch the POA from ATA to Int13 mode.
Related Article: SafeGuard Enterprise: Hotkeys and the POA