Swiflash PORT not found

[jyijyi]

have you tried to enter AT!BOOTHOLD first?

I just tried to enter AT!BOOTHOLD, after that it is OK to dowload FW by swiflash:

owner@ubuntu:~$ swiflash -m "wp76xx" -i /home/owner/Desktop/WP76xx_Release16.0.1_GENERIC.spk -p /dev/serial/by-id/usb-Sierra_Wireless__Incorporated_Sierra_Wireless_WP7607_VN73048508010300-if00-port0 
Detecting USB of the target
DONE
Communicating with the target
DONE
Downloading the firmware
..........................DONE
Rebooting the module
..........DONE
Firmware Download SUCCESS

BTW, you can also try MBPL fwdwl application to download FW:

How to update the RC7620 firmware with "qmi-update-firmware"

Can you try the MBPL R20 again? in AT command port, enter AT!BOOTHOLD, after that only /dev/ttyUSB is seen run the following (-f should be specify the folder): owner@ubuntu:~/QMI/MBPL_SDK_R20_ENG4-lite.src/SampleApps/lite-fw-download$ sudo ./bin/fwdwl-litehostx86_64 -m 4 -d /dev/ttyUSB0 -p /dev/cdc-wdm0 -t 1 -f /home/owner/Desktop/RC7620_FW/ Application version: 1.0.2105.3 INFO: QDL Port : /dev/ttyUSB0 INFO: Device Path: /dev/cdc-wdm0 INFO: FW Path : /home/owner/Desktop/RC7620_FW/ T…

fwdwl application can be downloaded here:
https://source.sierrawireless.com/resources/airprime/software/mbpl/mbpl-software-latest/