You will find an example of a 3-node Storage Spaces Direct Cluster (S2D) with one of the nodes having different versions of firmware on its drives. Below is a step by step guide on how to properly update the drive's firmware while the cluster is in production.

1.) Pause/Drain the node from the cluster and place the drives into a storage maintenance mode.

Suspend-ClusterNode -name “<Node Name>” -Drain 

Get-StorageFaultDomain -type StorageScaleUnit | Where-Object {$_.FriendlyName -eq “<Node Name>”} | Enable-StorageMaintenanceMode 

2.) Ensure that the drives are in a "maintenance mode".

3.) Download, install, and use Intel's SSD Data Center Tool - run the following command to list the Intel SSDs: 

PS C:\Program Files\Intel\Intel(R) SSD Data Center Tool> .\isdct.exe show -intelssd

4.) Use Intel's SSD Data Center Tool to perform the update:

.\isdct.exe load -intelssd # (where # is the index number of the specific drive)

5.) Once the update has completed on the necessary drives, reboot the host.

6.) Confirm that the update was successful:

7.) Take the drives out of the 'storage maintenance mode' and allow storage jobs to finish:

Get-StorageFaultDomain -type StorageScaleUnit | Where-Object {$_.FriendlyName -eq “<Node Name>”} | Disable-StorageMaintenanceMode 

8.) Resume-ClusterNode -Failback Immediate