Would someone please link me to the method for rolling back FF400 firmware and drivers to ones that work with SP3?  Thanks!

I've loved this thing. . . until now.   I'm on Windows XP SP3 and just updated my firmware drivers as recommended.  I run Sonar 8.53 and started noticing problems a few days ago after the update:  A whining particularly noticable in channels 1-4.  I didn't notice the crackling and poping in the headphones but I was mainly using an external converter and SPDIF to the FF.

Well, now I've been recording at 96k trying to use the now unusable channels 1 and 2 and I'm getting crackles and pops in the headphones.  I've never heard this before.  I've seen recommended on here and elsewhere that rolling back the firmware and drivers is the way to go.  Please let me know where to find how to do this.  I've searched "rollback" "drivers" "firmware" and other combinations and can't find it.  I simply want to get my FF400 back to its working state.  I'd love to get the "upgrade" if it's actually an upgrade in any meaningful sense for XP users; but cannot pay for such a thing at this time.

Thanks for any advice!