OPNsense on Older Lenovo ThinkCentre Error 1962 – No Operating System Found

[roshan.uddika]

Problem

OPNsense installs successfully to the internal SATA SSD, but after removing the USB installer the Lenovo stops with "Error 1962: No operating system found." The SSD is visible in BIOS and Windows can install and boot from the same SSD, so the storage hardware itself is not necessarily faulty.

What did not solve it

Normal ZFS installation using the installer's GPT/UEFI Hybrid layout.

Normal UFS installation using the GPT/UEFI Hybrid layout.

Changing only the BIOS boot order.

Using CSM/Legacy settings while leaving the disk in the installer's normal GPT layout.

Creating an MBR installation without ensuring the FreeBSD slice was marked active and legacy boot code was written.

Working solution

The successful configuration used an MBR disk, a FreeBSD/BSD slice containing a UFS root filesystem, the FreeBSD slice marked ACTIVE, and legacy boot code written to both the disk MBR and the BSD slice.

1. BIOS settings used

Setting - - Value

CSM -- Enabled
Boot Mode - Auto
Boot Priority - Legacy First
Secure Boot --Disabled
SATA Mode --AHCI

2. Create the MBR/UFS layout

1. Boot the OPNsense installation USB and start the installer.

2. Choose Other Modes → Manual (Manual Disk Setup).

3. Identify the internal SSD carefully. In this case it was ada0 (Lexar SSD NS100 256 GB). Do not modify the USB installer disk.

4. Delete the existing GPT layout on the target SSD.

5. With the target SSD selected, choose Create → MBR (DOS Partitions).

6. Select the MBR disk and Create a partition of Type: freebsd using the disk capacity.

7. Select the new BSD slice (for example ada0s1) and create a freebsd-ufs partition.

8. Set the UFS partition mount point to / (root).

9. Finish the installation.

3. Repair the legacy boot chain from the OPNsense USB

If the Lenovo still reports Error 1962, boot the OPNsense USB again, log in as root, choose console option 8 (Shell), and first verify the target disk:

gpart show ada0

gpart set -a active -i 1 ada0

gpart show ada0

gpart bootcode -b /boot/mbr ada0

gpart bootcode -b /boot/boot ada0s1

After setting the active flag, gpart show ada0 should show the FreeBSD partition with [active]. The exact disk/slice names may differ on another machine; verify them before running any write command.

4. Power off and test

sync

shutdown -p now

After shutdown, remove the installation USB and start the Lenovo from the internal SSD. With the tested machine, OPNsense then booted successfully.

Why this happened

The evidence points to a firmware/boot-layout compatibility problem rather than an SSD failure. Older Lenovo systems are known to produce Error 1962 with some FreeBSD/OPNsense GPT boot layouts. The successful workaround was to use the older BIOS/MBR boot path and explicitly complete the FreeBSD legacy boot chain.

Important safety notes

These steps erase the selected target disk.

Never assume the internal disk is ada0; verify it on the machine being repaired.

Never run the bootcode commands against the USB installer by mistake.

This is a workaround for affected legacy Lenovo firmware; modern UEFI systems should normally use the standard OPNsense installer layout.

Record the OPNsense version and exact Lenovo model/BIOS version when publishing results, because installer and firmware behavior can change.

Suggested community post title

[SOLVED] OPNsense Error 1962 / No Operating System Found on Lenovo ThinkCentre – MBR + Active Slice + Legacy Bootcode

Short post summary

OPNsense installed normally to an internal SSD but an older Lenovo ThinkCentre returned Error 1962 after reboot. The SSD was confirmed good by installing and booting Windows. Standard GPT/UEFI Hybrid ZFS and UFS installs did not solve it. The working solution was an MBR installation with a FreeBSD BSD slice/UFS root filesystem, marking the FreeBSD MBR slice active, then writing /boot/mbr to the disk and /boot/boot to the BSD slice using gpart. After removing the USB, OPNsense booted normally.

Reference links to include in the community post

OPNsense Forum – existing Lenovo ThinkCentre Edge 72 Error 1962 discussion

FreeBSD Forums – Lenovo Error 1962 / GPT versus MBR discussion

OPNsense Tutorials and FAQs – suitable section for a polished HOWTO

Community troubleshooting note • Created from a successful real-world recovery • September 2026

[nero355]

Can't you just update the BIOS/UEFI and be done with it ?!

Not that I have anything against manual partitioning ofcourse :)