[fprint] AuthenTec, Inc. AES2810 fails to work

[Tom Chiverton]

I've taken a fresh git clone of libfprint (commit
7eafca7babe40bc7dddd27ce9051b13b90ada021)
and built OK on Ubuntu 12.10.

My hardware is:
#lsusb |grep 281
Bus 001 Device 006: ID 08ff:2810 AuthenTec, Inc. AES2810

I'm using fprint demo v0.4 from the main repo. - I just copied my new
libfprint over the top of the system one.

I've setup udev rules and groups to grant my normal user access, and can
now enroll fingers from fprint.

But they never verify. I always get a status of 'finger does not match'
with minutiae numbers in the low tens.

Is there just a knack to this ?

Tom