[CentOS] rescue - UEFI revert to BIOS boot - how?

Tue Nov 20 12:39:56 UTC 2018
lejeczek <peljasz at yahoo.co.uk>

hi guys

I have a box on which UEFI boot has gone haywire and instead 
of boot it power the box down, that is before even going to 
grub2. (displays some error message)
I if change to BIOS boot then I can start Centos' rescue - 
my question is: how can I rescue, re-build grub so it would 
boot from tradition BIOS?

many thanks, L.