Could you please detail out the exact model of HP system? We can check to see if updated BIOS w/ FW that contains updated certificate hashes is available.
Also, take a look at this page:
Check to see that your ME firmware version has the supported certificate hash embedded.
Once you see the correct firmware version required for your specific model and certificate, you should be able to download it from your OEM.
Note that not all OEM's have the latest version of the firmware available.