It's not a bug, it's a feature
Since I added HxC support for the Amstrad some weeks ago I changed C & D for the CPC (and later for the Enterprise, too) into "HxC direct SD access for drive A" and "HxC direct SD access for drive B".
I was quite sure that no one will use 3 or 4 floppy disc drives today anymore, so I decided to do it like this, as it saves a lot of additional code.

I was quite sure that no one will use 3 or 4 floppy disc drives today anymore

It is reported by user, who use! See the config.

Can be the HXC support optional?

I think the best solution will be a Setup program or Config panel, or least INI file for define the floppy drives parameters.
Real drive or HXC, DD or HD, turbo modes, step rates.

(I am just curiouse: Is it more typically to have an HxC [with Zozos image selector ] or to have 4 drives connected to an EP?)

I'm in both team And where to count when two real drives and two HxC emulated drives used?

I know only 4 HxC EP user. And I think for the future the users will buy the direct SD interface for the EP, because will be more faster and comfortable. All Enterprise software are simple files on a FAT disks, then not need exact emulation of any disk image. And if anyone not have any storage device (just the tape player ), for using HxC also need to find EXDOS card, which is ultra rare...

HxC will be great device when having a big collection of computers. It is need a lot of money to buy best storage device for each, and many machine use a special disk format, and the programs need to use the original disk image, then floppy emulation important. The HxC solve the problem for all

Thanks a lot for testing EP Grandmaster ZOZO!!
Seems that this has to be modified for faster EP machines?

       ld b,8
        call mosdly0     ;delay
[...]

;### MOSDLY0 -> do delay
mosdly0 nop
        nop
        nop
        dec b
        jr nz,mosdly0
        ret
(part of the original source)

Does EGI have the same problem?

SymbOS contains a CPU speed test (it was originally done for the idle time measurement). I will try to use it for this issue!

I've just noticed that SymbOS seems to freeze (eg mouse pointer does not move anymore) after eg having out of memory error, or when I start SymShell (with more memory given - so it's not out of memory error in that case!).

Yes, I noticed this in JSEP, too. Sometimes it happens when moving the mouse inside the start menu, sometimes when starting SymShell, but it doesn't depend on the amount of Ram. A small part of the system is still working, at least the idle process is running, which I can see when pressing the "Z80" button. But most other stuff is freezing. As this problem never occures in Ep128Emu I wonder if it is a JSEP-specific problem or a problem with the mouse routines.

Also I guess it would be nice to create an EXDOS.INI file, so loading would be automatic. Also appending the URL above with &autostart=yes starts JSep emulation without clicking on the "Run" button, just clicking in the URL would be enough then.

What do I have to write into the EXDOS.INI file? Just
LOAD"SYM"
or something else?

And another trick: if you rename the SYM to START, then at BASIC prompt enought just press F1 key.