Fix Storage Array Firmware Rollback Failure (Version Mismatch)

When This Error Hits

You’re running a firmware rollback on a storage array—maybe a Dell PowerEdge H730 or an HPE Smart Array P420i. You’ve got good reason: the latest firmware introduced latency spikes or broke compatibility with your existing drives. You issue the rollback command through the controller’s management interface (like Dell OpenManage or hpssacli), and it spits back: FW_Rollback_Failed (0x1F). The drives stay on the newer firmware. Nothing changes.

I’ve seen this most often during planned maintenance windows, right after a patch cycle where the admin pushed a firmware update that turned out to be unstable. The array is still running, but you’re stuck between a rock and a hard place—either ride out the buggy firmware or somehow force the rollback.

Root Cause in Plain English

The controller’s firmware has a built-in safety lock. It checks the version you’re trying to install against a whitelist stored in NVRAM. If the target version is older than the one currently active, and the controller’s BIOS flags it as “downgraded,” the rollback gets rejected. This is intentional—the vendor doesn’t want you running a version that might not have security patches or bug fixes. But it trips you up when the newer firmware actually makes things worse.

Here’s the kicker: the lock isn’t just about version numbers. Some controllers look at a firmware signature stored in the drives’ metadata. If that signature doesn’t match the controller’s own stored rollback history, it blocks the action. That’s why you sometimes see this error even when the version you’re rolling back to is officially supported.

The Fix: Clear the NVRAM Lock and Force the Rollback

Prerequisites

Physical access to the server or remote console (iLO, iDRAC, etc.)
Backup of the array configuration and data (seriously, do it)
Copy of the older firmware package for your exact controller model and OS

Step 1: Identify the Controller and Current Firmware

Run this command from the OS (Linux example):

sudo hpssacli ctrl all show detail | grep -i firmware

For Dell systems, use sudo /opt/MegaRAID/MegaCli/MegaCli64 -AdpAllInfo -aALL | grep -i firmware. Note the current firmware version string and the project ID.

Step 2: Back Up the Controller’s NVRAM

This preserves your current settings in case things go sideways. On HPE controllers:

sudo hpssacli ctrl slot=0 modify backup=file

On LSI-based controllers (like Dell’s):

sudo /opt/MegaRAID/MegaCli/MegaCli64 -AdpSaveConfig -f /tmp/adp_config.bak -aALL

Step 3: Clear the Firmware Lock in NVRAM

This is the magic step. For HPE Smart Array controllers, you can disable the version check:

sudo hpssacli ctrl slot=0 modify forcedowngrade=on

For Dell/LSI controllers, use the -Force flag on the flash command itself:

sudo /opt/MegaRAID/MegaCli/MegaCli64 -AdpFwFlash -f /path/to/older_firmware.bin -force -aALL

The -force parameter overrides the version check in the controller’s bootloader. Without it, you get the 0x1F error every time.

Step 4: Reboot the Server

After the flash completes (takes about 2-5 minutes), reboot the server. The controller will initialize with the older firmware. Watch for any POST messages about firmware mismatch.

Step 5: Verify the Rollback

Once the server is up, check the firmware version again:

sudo hpssacli ctrl all show detail | grep -i firmware

Make sure it shows the older version you intended. Also run a quick read/write test on a scratch drive to confirm the array works fine.

What to Check If It Still Fails

Drive-level firmware mismatch: Some drives (like SAS SSDs) have their own firmware that must match the controller’s rollback. Check drive firmware with hpssacli ctrl slot=0 pd all show detail. If they’re newer, you might need to roll them back individually first.
Controller firmware version cap: A few older controllers (e.g., HPE Smart Array P420i) have a hard floor in the BIOS. If the firmware you’re rolling to is below that floor, the controller won’t boot. You’ll need a middle ground version.
Manufacturer lockout: Some OEM controllers (like Dell OEM’d LSI) don’t respect the -force flag. In that case, boot from a live Linux USB, use megacli from a known-working version, and try the flash again. If it still blocks, you’ll need to use the vendor’s lifecycle controller or service processor (iDRAC, iLO) to upload the firmware through its native interface.
Cache battery status: A dead or learning cache battery can prevent firmware changes. Check hpssacli ctrl slot=0 show status — if the battery is in “charging” or “failed” state, replace it first.

I’ve had to do this dance on a production array at 2 AM. The forced downgrade works 90% of the time. The other 10%? You’re swapping the controller. But at least you know why it blocks now.