Avidyne IFD540 Pilot's Manual page 204

NOTE
Each IFD Requires Separate Upload
In multiple IFD installations, the database uploads
must be performed individually for each IFD to be
updated.
Due to some of the upload durations, Avidyne recommends
creating a fob for each IFD to be updated so that the updates can
happen in parallel and not stacked serially, thereby extending the
overall time to accomplish a full update.
A clear indication is presented when the data uploads have been
completed. Likewise, if the USB fob was removed prior to
finishing the data upload, an error message will be presented and
the entire process will need to be manually restarted once the fob
is reinserted in the IFD.
Upload Complete Indications
When you are finished press the "Done" LSK, which will restart
the IFD into flight mode. Remove the USB fob and perform a
normal start up. It is highly recommended to verify the data was
6-28 General