I did everything in the list, and the code compiled after changing the SerialCloud.write to SerialCloud.print.
However, there’s nothing being sent via AT commands.
I noticed two things: The old passthrough firmware logs +UMWI: 0,1 - 0,4 and was able to handle unsynchronized responses such from AT+ULOC. Another thing is that I usually get ABORT and ERROR response from AT commands (when antenna is removed) from AT+UPSD=0,1 and AT+UPSD=0,3… but I did not get such this time.
To further my testing, I removed the SIM hoping to see ERROR message in AT+UPSD=0,1. Nothing shows in the log.