Have now upgraded to the latest firmware:

HC:NXS 5.34.2065
MC:5.20 5.20
Makes no difference. Same failures.

I turned on debug logging:
INFO	526.955078 sec	: Session log file /home/astroberry/.indi/logs/2022-05-20/indi_celestron_gps/indi_celestron_gps_19:35:29.log
DEBUG	551.499438 sec	: Connecting to /dev/serial/by-id/usb-Prolific_Technology_Inc._USB-Serial_Controller_COBIe108Y20-if00-port0 @ 9600
DEBUG	551.503902 sec	: Port FD 4
DEBUG	551.504011 sec	: Connection successful, attempting handshake...
DEBUG	551.504071 sec	: Initializing Celestron using Kx CMD...
DEBUG	551.504123 sec	: CMD <Kx>
ERROR	556.509289 sec	: Serial read error: Timeout error
DEBUG	556.559558 sec	: CMD <Kx>
ERROR	561.564823 sec	: Serial read error: Timeout error
ERROR	561.615042 sec	: Failed to communicate with the mount, check the logs for details.
DEBUG	561.615170 sec	: Handshake failed.

So, latest firmware, followed the instructions to align the mount first with the handset, disconnected the handset, plugged the connection to pi into the handset's port (not AUX), and still no connection. Help!

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