Hi Matthias, I looked deeper and can explain to you now, why I left the VOL key unassigned up to now.

After introduction and use of the remap-key feature I had to accomodate with new device operation
to press the I/O-, EQ-, SETUP- key longer, not to issue a re-mapped function.

At that point I didn't recognize, that its still possible to exit a menue by hitting the same key (short!) again
without issuing a remapped function.

This brought me to this kind of "workaround" to hit the VOL key 3x quickly instead, as its position is very thumb-friendly.

I hope I will get used now to exit menues by hitting the same button again, instead of using the VOL key.
EDIT: Just discovered that it will really take a while

But I think it would still be very useful to have
- EQ+B/T+Ld all
as it frees up one remap key location for another useful function.

While you are at it, maybe it would be worth to check for ease of use and "consistency",
whether also these functions could be implemented.
- Mono all
- Loudness all
- EQ out all
- BT out all

If you would ask me for a selection, whats more important that the other function,
then I would say
- EQ+B/T+Ld all (catches all of the others, Ld all, EQ out all, BT out all) and
- Mono all (to quickly check for Mono compatibility, how it sounds)

For my personal setup I am using now this:
- Vol key: Toggle Ph/Line
- I/O key: EQ+B/T+Ld 1/2
- EQ key: EQ+B/T+Ld 3/4
- SETUP key: Mute all

And it would be cool, maybe to be able to use this in the future:
- Vol key: Toggle Ph/Line
- I/O key: EQ+B/T+Ld all
- EQ key: Mono all
- SETUP key: Mute all

Many thanks.