spittet,
there are different reasons:
1.- oil industry financial crisis: companies want to minimize costs, they develop only 1 prototype in 1 year but may be next year they can built another 2 or 3, so they do not want to pay too much for firmware development becuase it is just 1 machine. Budget is limited.
as a developer I undertand that but if I am not able to personally download the firmware I will have to provide it to the customer so next time they develop a new equipment they may not contact me for the new flashing of controller or display. I know you can sign agreements but that will also increase the cost and after all if the equipment goes offshore you will never know about it.
alos if the management is changed it becomes more tricky.
so an easy way to countermeasure it is making it downloable only 1 time.
in this way I can reduce my cost because I know next time they need it they will have to contact me and I can chargue some royalty or so.
2.- as a freelance I want to do that
those are my basic reasons,
I aprecciate any help on that
Regards