I do not want the customer to be able to read the old code
The protect bits, at least, take care of that one.

One issue about security

there really are two kinds of security needs
a) protect against the thief that want to make a free copy.
b) protect against the sophisticated competitor.

and there is two kinds of need for security
a) protect against theft of the function
b) protects aginst the break of security features such a the password required to loot $1.000.000

if your situation is a) a) I would not worry too much; however if it is b) b) I know of no absolutely bulletproof means.

The thing that most often get lost is the relation between the cost of implementing security measures and the need for sophistication thereof.

The one security I know that works is make the hardware such that it can not be copied and let that be it.


Erik

A QUESTION: This will greatly affect your options. Do youn want 10.000 customers to do the upgrade or do you want 10 distributors/representatives to do it?


Erik