Xamiga segfaults with 16 bit on CV64

[Frank Wille <frank%phoenix.owl.de@localhost>]

Hi,

either it's me having done something stupid, or the Xamiga of 4.0 no longer
supports 16 bit screen depths. This is what I did:

---8<---
frank@phoenix grfconfig /dev/grf5
 1: 800x600x8   57.0kHz @ 92Hz flags: +hsync +vsync
 2: 800x600x16  57.8kHz @ 90Hz flags: +hsync +vsync
 3: 1024x768x8  72.8kHz @ 92Hz flags: default
 4: 1024x768x16 67.2kHz @ 83Hz flags: default
 5: 1152x900x8  68.9kHz @ 74Hz flags: default
 6: 1152x900x16 62.1kHz @ 66Hz flags: default
Console: 640x480 (80x60)        31.2kHz @ 59Hz flags: default
frank@phoenix cat .xserverrc 
X -dev /dev/grf5 -mode 2

frank@phoenix startx

The XKEYBOARD keymap compiler (xkbcomp) reports:
> Error:            Can't find file "amiga" for symbols include
>                   Exiting
>                   Abandoning symbols file "usa1"
Errors from xkbcomp are not fatal to the X server
Could not init font path element /usr/X11R6/lib/X11/fonts/CID/, removing from 
list!
X connection to :0.0 broken (explicit kill or server shutdown).
[1]   Segmentation fault      X -dev /dev/grf5...
---8<---

Further experiments have shown that it segfaults for mode 2, 4 and 6, but
works with mode 1, 3 and 5, i.e. 8-bit works, 16-bit doesn't.

Has anobody made the same observations?

How can I make Xamiga to write a core file when crashing?

-- 
    _  Frank Wille (frank%phoenix.owl.de@localhost)
 _ //  http://sun.hasenbraten.de/~frank/
 \X/   Phx @ #AmigaGer