DX4000 Recovery via ISO

WD have sent me an ISO for system recovery without data loss. Their phone support is terrible so better off asking people here since they have no live chat service. All I need to do is mount the ISO to USB then follow Step 9 on page 58 of the administrator’s manual to restore it back to factory settings without data loss, correct? Can anyone please confirm they have done this before and it has worked?

I confirm the procedure, if dony properly, works without data loss (only re-configure is needed). Please remember to use USB2 key (not USB3) of at least 16 Gb

Why USB 2.0 and not 3.0?

Hardware or software bug of either DX4000 or Windows 2008 OS. With 3.0 it will not work (at least this is what WD claims - http://support.wdc.com/knowledgebase/answer.aspx?ID=9889)