I had a similar event on a tsu3000.
My client claimed the pronto would lock up.
I took the pronto for 3 weeks and used it at my house with my program.
The remote worked great.
Last night I gave the remote back to the client downloaded his program into it
and if you were to hit the Ch+ and CH- at the same time the remote would lock up.
The firmware did not work. As long as you didnt hit 2 buttons at the same time
there was no problem.
I am curious if you problem is related in that we are using a corrupted file?
What do you think?