Trial with Diff9. Odd behaviour of Diff7 and Diff8 was confirmed fixed. To ease comparing with previous test, test No. is matched as before. So you would feel odd reading this file only. For internal disks, ZFS only have loader.efi. USB memstick has no ZFS and has loader.efi in UFS. ======================================================================== Output of gpart show with USB memstick attached. Note) diskid/DISK-S21MNXAG821947P is ada1. => 34 2000409197 ada0 GPT (954G) 34 2014 - free - (1.0M) 2048 409600 1 efi (200M) 411648 1024 2 freebsd-boot (512K) 412672 1024 - free - (512K) 413696 20971520 3 freebsd-swap (10G) 21385216 10485760 4 freebsd-ufs (5.0G) 31870976 1968537600 5 freebsd-zfs (939G) 2000408576 655 - free - (328K) => 34 488397101 ada1 GPT (233G) 34 2014 - free - (1.0M) 2048 204800 1 efi (100M) 206848 1024 2 freebsd-boot (512K) 207872 1024 - free - (512K) 208896 20971520 3 freebsd-swap (10G) 21180416 16777216 4 freebsd-ufs (8.0G) 37957632 450439168 5 freebsd-zfs (215G) 488396800 335 - free - (168K) => 34 488397101 diskid/DISK-S21MNXAG821947P GPT (233G) 34 2014 - free - (1.0M) 2048 204800 1 efi (100M) 206848 1024 2 freebsd-boot (512K) 207872 1024 - free - (512K) 208896 20971520 3 freebsd-swap (10G) 21180416 16777216 4 freebsd-ufs (8.0G) 37957632 450439168 5 freebsd-zfs (215G) 488396800 335 - free - (168K) => 3 1617794 da0 GPT (1.9G) [CORRUPT] 3 1600 1 efi (800K) 1603 34 2 freebsd-boot (17K) 1637 1614112 3 freebsd-ufs (788M) 1615749 2048 4 freebsd-swap (1.0M) ======================================================================== 1) Boot from ada0 WITHOUT USB memstick and ada1 attached (single drive). ada0 boots fine. >> FreeBSD EFI boot block Loader path: /boot/loader.efi Initializing modules: ZFS UFS Probing 6 block devices... boot1 imagepath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(1) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(4) probe: * supported (preferred) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) probe: * supported (preferred) done ZFS found the following pool: zsysS01 UFS found 1 partitions load: '/boot/loader.efi' spa: 'zsysS01', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) load: '/boot.config' spa: 'zsysS01', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) Failed to find '/boot.config' on pool 'zsysS01' (2) load: '/boot/config' spa: 'zsysS01', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) Failed to find '/boot/config' on pool 'zsysS01' (2) Starting '/boot/loader.efi' in 5 seconds....... Consoles: EFI console Command line arguments: loader.efi Image base: 0xdb727000 EFI version: 2.00 EFI firmwaew: L(rev 0.4960) ======================================================================== 2) Boot from ada0 without USB memstick attached (2 drives). ada0 boots fine. >> FreeBSD EFI boot block Loader path: /boot/loader.efi Initializing modules: ZFS UFS Probing 12 block devices... boot1 imagepath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(1) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(4) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(5) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(4) probe: * supported (preferred) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) probe: * supported (preferred) done ZFS found the following pool: zsysS02 zsysS01 UFS found 2 partitions load: '/boot/loader.efi' spa: 'zsysS01', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) load: '/boot.config' spa: 'zsysS01', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) Failed to find '/boot.config' on pool 'zsysS01' (2) load: '/boot/config' spa: 'zsysS01', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) Failed to find '/boot/config' on pool 'zsysS01' (2) Starting '/boot/loader.efi' in 5 seconds....... Consoles: EFI console Command line arguments: loader.efi Image base: 0xdb727000 EFI version: 2.00 EFI firmwaew: L(rev 0.4960) ======================================================================== 3) Boot from ada1 without USB memstick attached (2 drives). ada1 boots fine. >> FreeBSD EFI boot block Loader path: /boot/loader.efi Initializing modules: ZFS UFS Probing 12 block devices... boot1 imagepath: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(1) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(4) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(4) probe: * supported (preferred) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(5) probe: * supported (preferred) done ZFS found the following pool: zsysS01 zsysS02 UFS found 2 partitions load: '/boot/loader.efi' spa: 'zsysS02', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(5) load: '/boot.config' spa: 'zsysS02', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(5) Failed to find '/boot.config' on pool 'zsysS02' (2) load: '/boot/config' spa: 'zsysS02', devpath: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(5) Failed to find '/boot/config' on pool 'zsysS02' (2) Starting '/boot/loader.efi' in 5 seconds....... Consoles: EFI console Command line arguments: loader.efi Image base: 0xdb722000 EFI version: 2.00 EFI firmwaew: L(rev 0.4960) ======================================================================== 5) Boot from da0 [USB memstick] (3 drives). da0 boots fine. >> FreeBSD EFI boot block Loader path: /boot/loader.efi Initializing modules: ZFS UFS Probing 17 block devices... boot1 imagepath: pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(1) probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(4) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x0,0x0,0x0):hd(5) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(2) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(3) probe: . not supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(4) probe: + supported probing: pciroot(0x0):pci(0x1f,0x02):sata(0x1,0x0,0x0):hd(5) probe: + supported probing: pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(1) probe: . not supported probing: pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(2) vdev_read: failed dev: 0xdca15630, id: 1, lba: 32, size: 114688, status: 2 dskread: failed dev: 0xdca15630, id: 1, lba: 128, size: 8192, status: 2 probe: . not supported probing: pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(3) probe; * supported (preferred) probing: pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(4) probe: . not supported done ZFS found the following pool: zsysS01 zsysS02 UFS found 3 partitions Loading '/boot/loader.efi' from pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(3) Load complete Loading '/boot.config' from pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(3) Failed to lookup '/boot.config' (file not found?) Loading '/boot/config' from pciroot(0x0):pci(0x1d,0x00):usb(0x00,0x00):usb(0x01,0x00):hd(3) Failed to lookup '/boot/config' (file not found?) Starting '/boot/loader.efi' in 5 seconds....... Consoles: EFI console Command line arguments: loader.efi Image base: 0xdb727000 EFI version: 2.00 EFI firmwaew: L(rev 0.4960)