Unfortunately... Cromwell doesnt work very well on Xbox v1.6s without ripping the Xcodes from an MS bios. Your solution is to launch loader.xbe somehow rather than using the .bin.
The Xbox hardware is initialised at system startup based on information
stored in the Xcodes of the bios.
On the 1.6(b?) series Xboxes, Cromwell does not set up the memory timings
and other hardware initialisation sequences properly. This leads to system
instability and boot-time failures. Some symptoms of this problem post-boot
are kernel oopses and panics, and SIGSEGVs of userspace programs.
One day, hopefully, the Xcodes used on the 1.6 Xboxes will be reimplemented
in a clean-room fashion by the Xbox Linux team. However, this has not yet
been accomplished, and progress has been very slow.
Using this tool, you can build your own Cromwell bios image for your Xbox
using the Xcodes that are already stored in the Microsoft bios on your
system (and therefore, you are not infringing their copyright by obtaining
these from an illegal source).
it doesnt sound like you can grab them from 1.6(b?) anyway