The image starts to download from the server, but then after it runs for
a little bit, it switches to a bash prompt with a blinking cursor. The
image doesn't complete and the computer is left in an unusable state.

We had this problem before and we had to completely reformat and rebuild
a system for the imaging to work. I suspect that there is just something
on the computer we took the image from that is causing the image to fail,
but what it is we have no clue.