Resolved MacPro firmware 141.0.0 disabled USB ports on Win7

[SnakeCoils]

Lately, after upgrading my MacPro 2009 (previously flashed to 5.1) to the latest official 141.0.0 I noticed in BootCamp (Windows 7 64 bit Professional) a very strange issue...

All but one onboard USB ports are not more usable, the only functional is the one on the rear group, the middle of the three.

Looking at Hardware under Control Panel I can see many of USB Controllers not working (see attached image) but If I uninstall the tagged ones and redo an hardware refresh, they are working again and all USB ports are back to fully functional status (no more yellow triangles).

This until the next reboot...

I have already tried the usual ways of PRAM reset, SMC reset, reinstall BootCamp drivers but the issue remains. I am quite (although not absolutely) sure that until firmware 140.0.0 all the USB ports worked well since the first boot and Control Panel never reported problems.

So I have two choices: trying a (risky) downgrade to version 140.0.0 or waiting until the next major firmware upgrade in hope this issue will be resolved. I don't know if this happens also on Windows 8 or 10 but on Seven the issue is real.

This issue is present either after a reboot in Windows or a fresh boot from a previous OSX session.

 

[SnakeCoils]

Well, after some experiments with firmware v140 (thanks to the invaluable help of tsialex) I eventually went back to v141 and reinstalled Windows 7 from scratch in BootCamp partition (using BootCamp Assistant of OSX High Sierra) so everything is perfectly fine now, all USB ports are correctly recognized both under OSX and Seven.
However I noticed a thing during the installation: the BootCamp drivers automatically downloaded from Apple to the USB pen were the v4 version and NOT the v5 version.
In the previous install I leaved Brigadier to download the most recent BootCamp drivers and since the program recognized my Mac as a 5.1 machine it downloaded the v5 package but the original BootCamp assistant downloaded the v4 (4.0.4033) pack of drivers and this time I used the v4 drivers instead of v5 and after all the Windows Update steps the USB ports still works like a charm.
In the end the v141 firmware is not to blame at all for Windows troubles, it was purely a software (drivers) problem so if you plan to install Windows 7 on your MacPro 2009 upgraded to 5.1 it is better use the v4 BootCamp support files.
The Apple Software Update is broken in v4 but if you install the latest iTunes the most recent version of this application is installed along and it works as expected.