The problem is the board always goes to magenta mode after I flashed the code. I also tried to re-setup the board, but still, have the problem.
I understand it is the safe mode(magenta) which means that I cannot modify the firmware. But get confused about why the problem still happens after resetting and not sure how to fix it.
The argon will also go magenta if you are targeting a higher firmware version when flashing. This is normal as it updates your code as well as the OS. Let it finish, could be a few minutes, then it should reconnect.
Thanks, Mjones. Today, I tried to flash a new code which is working under manual mode,
SYSTEM_MODE(MANUAL)
SYSTEM_THREAD(ENABLED)
Then the red blinking seems to disappear. Also for another board with magenta light after flashing, after flashing the same new code, there is no magenta light any more.
At least, the boards are working now, although not sure why.