Wasn’t there a popup message telling you to close the dashboard tab? Because packages needed for displaying dashboard are also reinstalled, you have to reopen the dashboard to check whether FW update was successfully done - meaning even if FW update was success, the progress bar would still be stuck at 100% until you refresh the page.
If dashboard still shows old version of FW, then you can update bia SSH through:
cd /shares/Public
wget http://download.wdc.com/nas/sq-040001-623-20140904.deb.zip
unzip sq-040001-623-20140904.deb.zip
rm -f sq-040001-623-20140904.deb.zip
/usr/local/sbin/updateFirmwareFromFile.sh /shares/Public/sq-040001-623-20140904.deb
