My Book Live Duo 6 TB - Update Firmware on Airport Express while MBLD is "rebuilding"

Doing extensive reading on the WD community to get up to speed here, but I do have a question that needs attention:

Can I update the firmware on my Airport Express while MBLD is “rebuilding” (i.e. I recently changed “storage mode” from Raid 0 to Raid 1)? 

Airport Utility warns me: “This device and its network services will be temporarily unavailable. Are you sure you want to continue?”

No.

Wait until the drive finishes rebuilding

you can damage the entire partition if the process is interrupted some how while updating the router

Probably best to wait unti it finishes rebuilding. I went ahead at 86% and it did not interrupt the process. In total the rebuilding process took 20 hrs. for a Raid 1 (now 3TB) setup.

Thanks for responding Wizer.

Actually losing network connectivity during the brief time that the router is updating will have no effect on the My Book Live Duo's RAID rebuild.