PowerCLI - restoring backup has an error

I am trying out PowerCLI for the first time. 

I did a backup and  trying to restore it, but I get the error which looks to be something with the Source? 

Any ideas if i missed something?

thanks

PowerCLI C:\> Set-VMHostFirmware -VMHost 192.168.70.10 -Restore -SourcePath c:\ESXi-Backup\configBundle.tgz –HostUser root  -HostPassword ********* -Force

Set-VMHostFirmware : 6/4/2019 9:25:32 AM        Set-VMHostFirmware              A general system error occurred: Internal error

At line:1 char:1

+ Set-VMHostFirmware -VMHost 192.168.70.10-Restore -SourcePath c:\ES ...

+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : NotSpecified: (:) [Set-VMHostFirmware], SystemError

    + FullyQualifiedErrorId : Client20_SystemManagementServiceImpl_RestoreVmHostFirmware_ViError,VMware.VimAutomation

.ViCore.Cmdlets.Commands.Host.SetVMHostFirmware

VMHost               UploadUrl

------               ---------

1. 192.168.70.10  http://192.168.70.10/tmp/configBundle.tgz