CX CAS stuck at boot (No response to any recovery key combin

[enumc]

Yes, while pressing and releasing the reset button.

I must be missing something. After pressing the "Doc+Enter+2" and reset, the calculator reset with 0% progress bar. However, I don't see anything in the serial monitor. I hooked up RX <-> TX, and TX <-> RX, as well as the 2 GND pins to ground.

[enumc]

Here's all I see in the serial monitor. I have set baud rate to 115200.

[critor]

You don't need both grounds.
Just connect the easiest one for you.

If you're seeing garbage, it may be that the connections are wrong or poor.

Be sure that all other settings are right too, not just the baud rate :

Baud rate : 115200
Data : 8 bit
Parity : none
Stop : 1 bit
Flow control : none