Comment 2 for bug 1876848

Wow what a confusing error message, I'm sorry about this!

This seems to be caused by the fact that both disks in the curtin config have the same wwn:

   - {ptable: gpt, serial: Corsair_Force_GS_13207907000097410026, wwn: '0x0000000000000000',
     path: /dev/sda, preserve: true, name: '', grub_device: true, type: disk, id: disk-sda}
   - {ptable: gpt, serial: Corsair_Force_GS_1320790700009741003D, wwn: '0x0000000000000000',
     path: /dev/sdb, preserve: true, name: '', grub_device: true, type: disk, id: disk-sdb}

This seems to come straight from the udev database:

 P: /devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/block/sda
 ...
 E: ID_WWN=0x0000000000000000
 E: ID_WWN_WITH_EXTENSION=0x0000000000000000

(and same for sdb). This in turn seems to be because SCSI_IDENT_LUN_NAA_LOCAL is 0000000000000000 (from 55-scsi-sg3_id.rules) for both drives and I'm fairly sure that's something sg_inq --export spits out but now we're really running into the limits of my knowledge I'm afraid. There's a bug somewhere, maybe in your drives firmware or maybe in sg3-utils...