Hi JerryChang,
Did you mean the changes related to software or hardware? For software, I tried with Jetpack 4.2.1, and changed the command line argument, like adding console=ttyTHS1 and early_printk, as can be followed in our previous discussion: How to obtain UART logs on Jetson Nano production modules, over UART 2 - #10 by jetson_user. We also tried with Jetpack 4.6 and 4.5.1, and still the booting is stuck, for some of the Nanos. Of course, at this moment we are able to get the UART logs. And we have resumed with Jetpack 4.2.1, because our drivers are based on that.
For hardware, I will have to get back to you with the details.
The bad device message also appears for the booting case, in the logs: UARTLogsNanoBooting. So might this still be the issue?