Hmmm, I did flash TinyBasic and the behavior is different, even after disconnecting power completely for 1 minute "sudo screen /dev/ttyACM0 9600" connects successfully:
HELLO
TinyBasic Plus v0.14
90865 bytes free.
OK
>
How can the Due bootup process be different for "Blink" vs. "TinyBasic"?
Hermann.