I'd be pretty worried about it, you may have bricked the unit and only HB would be able to bring it back to life in that case. The current firmware in the unit is erased and then reloaded during the update process. If it erased and only partially reloaded........sounds bad.
You never want to disturb power or the unit in any way while it is updatiing. I am always connected to a battery when updating to prevent a problem in case of a power bump.
The recommended process for reloading is to have the unit fully started up and then insert the card....If it won't start up, you could try inserting the card and then power up to see if it does anything......Otherwise give HB customer service a call.