Porting NetBSD to the Zipit Z2 XScale handheld

["lausgans%gmail.com@localhost" <lausgans%gmail.com@localhost>]

I'm interested in porting NetBSD to the Zipit Z2 clamshell device
(poor-man's analog of Sharp Zaurus).
Here are the specs: http://linux.zipitwireless.com/wiki/Z2
Originally it comes with bootloader called blob:
http://linux.zipitwireless.com/projects/z2kernel (was it used to load
NetBSD kernel ever?) and runs cutted Linux-based firmware.
Anyway, the blob is pretty limited and can't even load kernels from an
external SD card:
http://zipitfan.wordpress.com/2011/02/02/z2-bootloaders/ so the port
of U-Boot loader was unrolled which raised the availability of many
Linux distros for the device. It meant to be flashed in place of the
stock loader.
Now, what is the most appropriate existing arm port to start with? I'm
seeing the only ports that include PXA270 support are evbarm, hpcarm
and zaurus. I suppose the relevant among them are hpcarm and zaurus,
as evbarm has nothing about mobile device periphery like lcd and
keyboard. However, evbarm has U-Boot image rules in makefiles for some
machines it covers.
So i've started by rewriting init files from the hpcarm's WZERO3 and
producing uimg like in evbarm. However U-Boot rejects to load the
final image with address/instruction related errors. What addresses
should i use? The ones used to load Linux kernels don't work as well
as those which are used for machines in evbarm port.
Thanks for any help!