> concise explanation for the 42x problem / fix.
> What was broke and how was it fixed and tested

when asked to stop flying the 425 two issues
remained... a startup issue and restarting
the "full navigator" after the loss of gps.
http://rob.com/lancair/flights/kirk/

many issues were found and fixed in these early days
and xbow had great turnaround once armed with
raw data to address the early ugly issues.
They were a joy to work with and the 425 is
much faster and responsive than the 500. path quickening
for the flight path marker can tightened and
its a joy to fly an overhead with the dot exactly
on the runway and smack it with high AOA. something
that could never be done with a massively dampened 500.

its reasonable to assume these known issues
were addressed.

I've never flown a pinpoint/chelton, but I've seen
the insides.

Rob