Boot Loader LED 9 Blinks


Hello Friends,
my program downloads into my Teensy 4.0 just fine.
and the Teensy Loader says: "Reset OK".
and the program starts, and runs without a problem.
but if I power it off, then when I power it back on, I get the Boot Loader 9 Blinks.
"a software crash resulting in hard fault or CPU lockup (typically very early in startup) can result in this error"

can anyone make a suggestion on how to debug this?
is there a way to know where in "very early startup" this problem can happen?
after what point in "startup" does the 9 Blinks no longer happen?

Thanks for your help.

Thanks for your quick reply.
my program is large, with a number of local libraries, etc.
I have written a smaller program to try and isolate the problem, but the problem goes away when I make the program smaller.
for example, the large program uses 3 CAN ports, if I comment out my code, so that it uses 2 CAN ports, the problem goes away.
should I make a ZIP file with all the code, and upload that?
Sorry I can't provide a simple test program.. :-(
I made a ZIP file with all the source code.
see attached..
I can also provide the .ELF file, if that is helpful.


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