X in 16bpp on an NC?

Hi,

I've managed to get NetBSD/acorn32 1.6 running on my NC at last. Does anyone 
know if it's possible to get X running in 16bpp mode, though?

If I just start X without any preamble, I get 640x480x8bpp. If I use 
'setdisplay -x 640 -y 480 -c 16', the machine reboots when I try to start X. 
(I had to tweak setdisplay to get it to compile; IIRC, I had to change 
vidc->bitsperpixel to vidc->log2_bpp - this seems to work OK when I specify 
-c 8 on the command-line, though.)

tia,

Stephen