how to trace a microcontroller running it's app ?

I ran into quite a number of problems of that sort in APPLE II assembly code where whatever system generated the code would intersperse defined constants with the generated code. The disassembler would try to disassemble string constants and debugging data (such as function names, etc.) and would then miss the first instruction of the next function.

Sometimes you may have to look at instructions such as LJMP 096F and make sure that the bytes at 096F really are executable code.

It's little things like that which make disassembling and reverse engineering a non-trivial excercise. Which is OK by me as it paid the bills for almost half a year back in the '80s.

Mark Borgerson