[CentOS] HP Envy EFI problem after BIOS update

Thu Sep 15 11:58:20 UTC 2016
Gary Stainburn <gary at ringways.co.uk>

Well that's me stuffed again,

I did get to the point where I could press F9 and then select the Centos EFI 
entry.

The problem only occurred after Windows installed a BIOS update, taking me 
from F.65 to F.67.  One of the first things I did to try to fix the problem 
was to roll back F.65.

This morning I thought I would re-apply the update and see if it made any 
difference.  Unfortunately it did. Wnce I was on F.67, when I pressed F9 the 
menu was missing the Centos option, only showing "

OS Boot Manager
Fedora (ST1000LM014-1EJ164-SSHD)
Boot From EFI File

While collecting the above details, I tried the last option which then gave me 
the options:

NO VOLUME LABEL
<EFI>
<centos>
shim.efi

At which point Centos then booted.

Anyone got any ideas what I need to do next.

Also, I tried rolling back to F.65 again to see if that would return the 
Centos option to the F9 menu but it didn't