Eh... Not quite exactly, there was a bugged version of 2.6 that didn't work the pad hook keys actually, at least if you run with USB Loader GX but it still worked fine with DML Booter, dunno if that was fixed or not but I upgraded to 2.8 when it came out and it works!
Off my experience WD is really good with Dios Mios, ever since I upgraded to a 500GB WD HDD all my Dios Mios problems were gone (well except for known ones like incompatible games and audio streaming of course) but it's recommended to disable Sleep Mode first!
Here follow these steps:
http://wdc.com/wdproducts/wdsmartwareupdate/wdsmartware.asp?id=wdfGeneric&os=win
It's called "Smartware update" and is made by the official company, but make sure to back up your data first because it will erase the data for formatting purposes!