i have install the AUdya4 54C.
I had the same problem again as with 54D I
could not save the Master1.
Now I finally got the right hint from Ketron.
And it works, very well.
I am very satisfied with the 54C.
All O.S. versions of Audya 4 allow to memorize
the 5 functions: 3 for keyboard (GENERAL MASTER1 MASTER2))
plus 2 for accordion (ACCORD1 ACCORD2).
On the Audya 4 the Mode Accordion is always ACTIVE by DEFAULT.
If you need to use all 5 functions available on the Menu
KEYBOARD CONTROL > ACCORDION" you have to disable, AT THE START,
the Mode ACCORDION and SAVE it on the Menus: ACCORDION, AND ON CUSTOM STARTUP