Azure VM bios version changed after reboot (OpenBSD/Linux)

Adriaan 0 Reputation points
2026-08-26T20:05:21.7333333+00:00

I am using azure to host an OpenBSD custom image based on Version 7.7.

Before a routine reboot, I was getting:


bios0 at mainbus0: SMBIOS rev. 2.3 @ 0xf93d0 (338 entries)

bios0: vendor American Megatrends Inc. version "090008" date 12/07/2018

...

hvs0 at hyperv0 channel 3: ide, protocol 6.2

scsibus1 at hvs0: 2 targets

sd0 at scsibus1 targ 0 lun 0: <Msft, Virtual Disk, 1.0> naa.xx

sd0: 131072MB, 512 bytes/sector, 268435456 sectors, thin

hvn0 at hyperv0 channel 11: NVS 5.0 NDIS 6.30, address xx:xx

hvs1 at hyperv0 channel 12: scsi, protocol 6.2

scsibus2 at hvs1: 2 targets

hvs2 at hyperv0 channel 13: scsi, protocol 6.2

scsibus3 at hvs2: 2 targets

sd1 at scsibus3 targ 0 lun 0: <Msft, Virtual Disk, 1.0> naa.xx

sd1: 32768MB, 512 bytes/sector, 67108864 sectors, thin

Now, after a reboot, I am getting 


bios0 at mainbus0: SMBIOS rev. 2.3 @ 0xf93e0 (338 entries)

bios0: vendor American Megatrends Inc. version "090008" date 02/27/2023

...

wd0 at pciide0 channel 0 drive 0: <Virtual HD>

wd0: 128-sector PIO, LBA48, 131072MB, 268435456 sectors

wd0(pciide0:0:0): using PIO mode 4, DMA mode 2

The hvs0 driver is no longer being detected (along with my data disk), and the only thing that seems to have changed is the bios version. What can I do to get my data disk back?

Azure Disk Storage
Azure Disk Storage

A high-performance, durable block storage designed to be used with Azure Virtual Machines and Azure VMware Solution.

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  1. Zoha Fatima 510 Reputation points
    2026-08-27T11:42:11.86+00:00

    Hi Adriaan,

    The changed BIOS date indicates that Azure moved the VM to a host with newer virtual firmware. The disk itself is probably still intact; OpenBSD is no longer detecting the Hyper-V synthetic storage controller (hvs), so the SCSI-attached data disk cannot appear.

    First, confirm under Azure VM → Disks that the managed data disk remains attached, then create a snapshot. Next, use Redeploy + reapply to move the VM to another host. If hvs remains unavailable, attach a disk created from the snapshot to another compatible OpenBSD VM using Attach existing disk.

    Please also open an Azure Compute support case with both boot logs, as this appears to be a host-compatibility regression involving the custom OpenBSD image. Do not initialize or format the missing disk.

    Thank you, and feel free to respond back for more assistance.

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