Jchetan , ScrJeff Normally, it should take about 24 hours for drivers to start showing up... however, this feature has been so popular some of the processing is taking a bit longer than we expect and so it is taking a bit longer in some cases. Thank you for being patient, and we are working on streamlining the processing to get back to the 24 hours target.
IndiaYankee , it is looking like you have everything I can imagine configured correctly. I'd like to get more information so we can investigate more deeply. For DM, can you direct message me in tech community? Click on my name, and when my profile comes up, click "Message" in the upper-right. Or... open a support ticket, which I'd actually like to start getting a few more so we can track and route these to engineering for investigation more formally. Let them know I asked, and to put your "IndiaYankee" into the comments so I can identify it!
Summa040, nearly all BIOS and UEFI updates use a "secure install" method that allows them to be securely updated via Windows Update without requiring a bitlocker password. However, that approach does require the publisher to build the update the right way to take advantage of that mode. It seems you found one of the few that doesn't do that correctly. So, I would pause that driver update, and any other similar ones and contact HP to inform them of the issue and ask if they've fixed it, or can fix it, in a newer issue. This is one reason that even though driver updates have a low rate of issues, there are still some... so we still recommend using 2-3 policies as deployment rings. Put a few representative devices in the first ring to do some initial testing of the drivers, before approving in later rings. With automatic approval policies, use increasingly bigger deferral days to spread out when they start so you can complete the validation before the next group starts. You can see more info about "rings" by searching online, or starting here: https://learn.microsoft.com/en-us/windows/deployment/update/waas-configure-wufb#start-by-grouping-devices
HTH!
-David