ESXi Host Rolls Back to Previous Version After Upgrade

Products

• VMware vSphere ESXi

Issue/Introduction

• Attempted to upgrade the VMware ESXi host to a newer version (e.g., from ESXi 6.7 to 8.0 or a newer patch level). The upgrade process appears to complete successfully, and the host reboots. However, upon the next boot cycle, the host has reverted or rolled back to the previous/older ESXi version that was installed before the upgrade.
• This behavior is typically unexpected, as logs may confirm the host successfully reached the newer version at one point, yet the permanent change fails to commit.
• The standard method for manually reverting a patch or update is the Shift + R option during boot. This was not the cause here.
• The ability to revert to a previous ESXi version is generally not possible after upgrading to ESXi 7.0 (and newer) due to significant changes in the boot partition layout and structure. If the upgrade were properly committed, reversion would not be possible.
• The host is configured to boot from a Dual SD card setup in a RAID configuration.

Environment

• VMware vSphere ESXi 6.x
• VMware vSphere ESXi 7.x
• VMware vSphere ESXi 8.x

Cause

• The ESXi host reverting to an older version post-upgrade is fundamentally a hardware configuration failure, not a typical software rollback. This occurred because the host utilizes a Dual SD Card RAID setup for booting. While the upgrade (e.g., to ESXi 8.0U3) was initially applied, the process failed to permanently commit because the SD card RAID mirror went faulty.

Resolution

To resolve the rollback issue permanently and ensure future stability, follow the below steps:

• Backup the existing ESXi host configurations. Refer How to back up and restore the ESXi host configuration.
• Replace SD Card Boot Device with Supported Media.

NOTE: The underlying issue is a faulty SD card RAID array combined with the use of a device (SD card) that is no longer recommended or fully supported for persistent boot installations in modern ESXi host versions (ESXi 7.0 Update 3 and later). Refer ESXi System Storage When Upgrading

• Re-install the ESXi host with the same image. 
  • Boot from Installer: Boot the host using the ESXi Installer ISO for the target version.
  • Select New Device: During installation, select the new NVMe/SSD boot device as the installation target.
  • Complete Installation: Allow the installation to complete, and reboot the host. The host should now persistently boot into the correct version.
• Restore ESXi Configuration. Refer How to back up and restore the ESXi host configuration