Need help with flashing 4.1 to 5.1

This is a single processor system with a 2.66 Ghz Quad-Core Intel Xeon.

I tried using "Mac Pro 2009-2010 Firmware Tool" to flash from 4.1 to 5.1.

Initially I received error 5570. Then I downloaded MacProEFIUpdate.dmg and opened it.

When I ran Mac Pro 2009-2010 Firmware Tool the second time I ran through to completion without error.

Then I shutdown my Mac Pro. For some reason the screen went black but the mouse pointer remained. After waiting several minutes I used the power button...

Need help with flashing 4.1 to 5.1