Mac Pro 2009 4,1 upgraded to 5,1 lost boot logo on flashed Radeon 6870
'''Everything happened after High Sierra firmware update in my three Mac Pros :(
Basically flashed Mac Pro 4,1 to 5,1 which had to be genuine Apple flashed to install High Sierra with flashed EFI Radeon 6870 to see boot logo.
All My Radeons were display EFI Apple logo - now they don't :(
How to restore boot logo? :('''
Is this a good question?