Mac Pro 3.1 USB ports die with Mountain Lion

[pronicd1]

Hi all, new here, so apologies if it's bad etiquette by starting off picking some brains!
I have used macs for many years and have had plenty of different ones, but have never had major problems like I am currently experiencing with my Mac Pro 3.1
If I try to run on Mountain Lion or later the USB ports die.
I have tried all the usual things and have had discussions with Apple and various independent techies and they advise me that there may be a hardware fault (Apple Store hardware test ran ok) or a firmware problem.
I have downloaded and tried to run the Apple firmware restore CD which does nothing.
Is there a way to flash new firmware?
Or is my only option to get a new logic board (or get someone to do it for me….)?
Assuming that is that there isn't anywhere where you can get them properly tested and repaired down to component level.

Appreciate your thoughts!
[doublepost=1456450861][/doublepost]Hmmmm, just after posting this I found Will the Plank's and others posts about the very same issue!
Hopefully the wi-fi card may solve it as my machine has an Atheros one fitted…...

 

[nigelbb]

The quick cheap fix that would also be a real upgrade not just a fix would be to add a cheap USB 3.0 PCIe card.

 

[bax2003]

That sounds like Mac Pro 1.1, and somebody who made bootable installer of Mountain Lion using MLPostFactor.....many people had problems with USB, Sound etc.

DiskMakerX is tool for making bootable USBs. If you have Mac Pro 1.1/2.1 use SFOTT.

 

[pronicd1]

That sounds like Mac Pro 1.1, and somebody who made bootable installer of Mountain Lion using MLPostFactor.....many people had problems with USB, Sound etc.

DiskMakerX is tool for making bootable USBs. If you have Mac Pro 1.1/2.1 use SFOTT.

[doublepost=1456533207][/doublepost]I am really pleased to say that I have removed the Airport Express Card and this beast is now running perfectly in Mountain Lion! Hooray!! TWO months this has taken to resolve and no thanks go to numerous people at Apple, so called genii at an Apple Store and various techies at four other companies.