[Help] F2-423 Failed TOS 5→6→7 Upgrade: UEFI Shell Stuck, Bootloader Partition Lost & Clean NVMe/SSD Install
Posted: 11 Sep 2026, 00:55
Model: TerraMaster F2-423 (Intel Celeron N5105)
Target Goal: Perform a clean TOS installation on a new SSD (and ultimately migrate the OS boot drive to NVMe), then safely remount the original RAID 1 array, or recover the data from the RAID 1 array, and use a single disk.
Background & Sequence of Failure:
Failed Upgrade Sequence: The issue originated while attempting an OS upgrade path from TOS 5 → TOS 6 → TOS 7.
Web Access Loss: Mid-upgrade, the web UI became inaccessible.
SSH Recovery Failure: Attempted to log in via SSH to repair/update the installation manually. The OS crashed further during this process, dropping network access entirely.
Current Diagnostic Setup: Connected an HDMI monitor and USB keyboard directly to the NAS. The unit now either loops/beeps every 30 seconds or drops directly into the UEFI Interactive Shell (Shell>). LAN port LEDs remain dead.
Hardware Isolation Steps Performed:
Motherboard Health: Verified hardware health by booting a spare Windows SSD via HDMI. The NAS POSTs and boots Windows perfectly, proving the CPU, RAM, and board controllers are functional.
Data Preservation: Pulled the original two 12TB HDDs (configured in RAID 1 with all personal data backed up) to keep them safe from accidental formatting. Removed 2 NVMes.
USB Flash Attempts: Attempted to re-flash the internal 240MB USB boot drive using official recovery image (common_bootloader_V5.1.48.img).
Flashing Tools Used: Rufus, balenaEtcher, both gave me errors, but I ignored them. Also used Win32 Disk Imager.
Errors Encountered: balenaEtcher throws a "Missing partition table" error. Inspecting/extracting the image payload reveals Linux root system folders (/www, /etc, /sbin, /usr) rather than an executable EFI/BOOT/bootx64.efi partition structure.
UEFI Shell Mapping: Running map -r in the UEFI shell only lists block devices (blk0, blk1), with no filesystem mappings (fs0:, fs1:) available, preventing execution of startup.nsh or .efi files.
Questions for TerraMaster Support / Community:
Can you provide a link to a full, pre-partitioned raw USB disk image (containing a valid MBR/FAT32 EFI boot partition) for the F2-423 rather than the raw OS rootfs payload?
What is the recommended procedure to execute a fresh TOS 5 or TOS 6 install on a new SATA SSD (or NVMe drive) using the clean bootloader once network access is restored?
What is the proper sequence to safely re-insert and remount the original 12TB RAID 1 storage pool without the installer forcing an array re-initialization/format?
Target Goal: Perform a clean TOS installation on a new SSD (and ultimately migrate the OS boot drive to NVMe), then safely remount the original RAID 1 array, or recover the data from the RAID 1 array, and use a single disk.
Background & Sequence of Failure:
Failed Upgrade Sequence: The issue originated while attempting an OS upgrade path from TOS 5 → TOS 6 → TOS 7.
Web Access Loss: Mid-upgrade, the web UI became inaccessible.
SSH Recovery Failure: Attempted to log in via SSH to repair/update the installation manually. The OS crashed further during this process, dropping network access entirely.
Current Diagnostic Setup: Connected an HDMI monitor and USB keyboard directly to the NAS. The unit now either loops/beeps every 30 seconds or drops directly into the UEFI Interactive Shell (Shell>). LAN port LEDs remain dead.
Hardware Isolation Steps Performed:
Motherboard Health: Verified hardware health by booting a spare Windows SSD via HDMI. The NAS POSTs and boots Windows perfectly, proving the CPU, RAM, and board controllers are functional.
Data Preservation: Pulled the original two 12TB HDDs (configured in RAID 1 with all personal data backed up) to keep them safe from accidental formatting. Removed 2 NVMes.
USB Flash Attempts: Attempted to re-flash the internal 240MB USB boot drive using official recovery image (common_bootloader_V5.1.48.img).
Flashing Tools Used: Rufus, balenaEtcher, both gave me errors, but I ignored them. Also used Win32 Disk Imager.
Errors Encountered: balenaEtcher throws a "Missing partition table" error. Inspecting/extracting the image payload reveals Linux root system folders (/www, /etc, /sbin, /usr) rather than an executable EFI/BOOT/bootx64.efi partition structure.
UEFI Shell Mapping: Running map -r in the UEFI shell only lists block devices (blk0, blk1), with no filesystem mappings (fs0:, fs1:) available, preventing execution of startup.nsh or .efi files.
Questions for TerraMaster Support / Community:
Can you provide a link to a full, pre-partitioned raw USB disk image (containing a valid MBR/FAT32 EFI boot partition) for the F2-423 rather than the raw OS rootfs payload?
What is the recommended procedure to execute a fresh TOS 5 or TOS 6 install on a new SATA SSD (or NVMe drive) using the clean bootloader once network access is restored?
What is the proper sequence to safely re-insert and remount the original 12TB RAID 1 storage pool without the installer forcing an array re-initialization/format?