A little bit of Feedback:
After a few more seconds, JF will automatically restart.
NB: IMPORTANT! TURN OFF YOUR SYNTH! REMOVE THE CABLE FROM YOUR SOUNDSOURCE, THEN FROM THE RUN JACK, AND RESTART. THIS IS TO MAKE SURE JF WON'T DAMAGE YOUR SOUNDSOURCE.
This somehow scared me off the update procedure. For me it reads a bit like a timing critical thing ("Turn off quickly after the update procedure!") But to me it's not precisely clear what is indicating:
JF will automatically restart.
If the warning is indeed because of the problem in the above mentioned MF thread (with -12v exposed while inserting/removing the cable on the run socket ), I'd change the instructions to emphasize turning off the synth BEFORE removing the cable, to make more clear what's important. Just my two cents after a quick read. Wish I had time to actually play with it.