This firmware release is just unacceptable for Mac OS X.
The browsing is much much much slower than the previous version. I lost a loooooooooooot of time reinstalling my iMac thinking that this would be the problem.
It is unacceptable from the WD development team to release such untested firmware.
If any other Mac users are experiencing, just like me, and there are probably thousands... just downgrade to the version before. Speed will come back.