Normally new FW is updatable but before that please provide your result ATI9, AT+KGSN=2(IMEI), AT+KGSN=3(FSN).
Yes. Youu can set USB ONLY without UART1 at all by (AT+KUSBCOMP=1.
(debug port UART0 is not impacted)
Here’s the syntax:AirPrime - HL78xx - AT Commands Interface Guide - Rev8.1.pdf (1.9 MB)
AT+KUSBCOMP=
USB mode config
0 USB disabled (default)
1 3 CDC-ACM mode (PID: 0xC001)
USB-ACM0 - AT/PPP port
USB-ACM1 - PPP data port
USB-ACM2 - NMEA data port
Notes
The configuration is kept in flash.
New configuration will only be activated after module reboots.