The Core didn't connect to the cloud after waking up from a pin triggered sleep

Hello @ScruffR
Starting with the suggestion that you told me about flashing via USB, right now I'm doing particle flash --usb tinker when my device is stuck in the sleep mode. Then, I re-flash it again with the modified code that I have to avoid the factory reset. Secondly, I removed pinMode(RxPin, INPUT); since it will set by the Serial2.h as you told me, and I didn't know that before. I don't know what you mean by saying:

And if there is a disadvantage if I'm using the pull-down resistor with my remote device?

For the:

I tried to follow your previous suggestion in other thread to use pre-flush in my code since you advised me to do it before the read:

At the end, I'm still couldn't make my device connect to the cloud after waking up from the triggered pin sleep.
Thanks.