Hello Again,
Thank you for the response.
Assume a reboot will be needed after the update is applied and smartpath can be left enabled.--- Yes you are right, reboot is required for the changes to take place.
You can start with downloading the latest compatible SPP for gen9 and then add the components (RPM) manually as mentioned in the doc file which I uploaded. Please do not miss to tick the "Make Bootable ISO File" option. Before you add the files manually please check the content report for that particular SPP as the desired firmware file may be already present in it.
https://techlibrary.hpe.com/us/en/enterprise/servers/products/service_pack/spp/index.aspx
Document has been uploaded, hope it helps.
Cheers!