Lost l4tbr0 after flashing the image

Hi ,

In our production line . we found out that after flashing the image sometimes i dont see 192.168.55.1. if we flashing the same image again . it works. could you help to see what might go wrong ?

sudo systemctl status nv-l4t-usb-device-mode.service
[sudo] password for vaitl:
● nv-l4t-usb-device-mode.service - Configure USB flashing port for device mode
Loaded: loaded (/opt/nvidia/l4t-usb-device-mode/nv-l4t-usb-device-mode.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2018-01-28 23:58:26 CST; 2 years 4 months ago
Process: 4461 ExecStopPost=/opt/nvidia/l4t-usb-device-mode/nv-l4t-usb-device-mode-stop.sh (code=exited, status=0/SUCCESS)
Process: 4036 ExecStart=/opt/nvidia/l4t-usb-device-mode/nv-l4t-usb-device-mode-start.sh (code=exited, status=1/FAILURE)
Main PID: 4036 (code=exited, status=1/FAILURE)

Jan 28 23:58:22 localhost nv-l4t-usb-device-mode-stop.sh[4461]: /opt/nvidia/l4t-usb-device-mode/nv-l4t-usb-device-mode-stop.sh: line 34: ech
Jan 28 23:58:22 localhost nv-l4t-usb-device-mode-stop.sh[4461]: rmdir: failed to remove ‘l4t/configs/c.1/strings/0x409’: No such file or dir
Jan 28 23:58:22 localhost nv-l4t-usb-device-mode-stop.sh[4461]: rmdir: failed to remove ‘l4t/functions/ncm.usb0/’: No such file or directory
Jan 28 23:58:22 localhost nv-l4t-usb-device-mode-stop.sh[4461]: rmdir: failed to remove ‘l4t/functions/ecm.usb0/’: No such file or directory
Jan 28 23:58:22 localhost nv-l4t-usb-device-mode-stop.sh[4461]: rmdir: failed to remove ‘l4t/functions/mass_storage.0/’: No such file or dir
Jan 28 23:58:22 localhost nv-l4t-usb-device-mode-stop.sh[4461]: rmdir: failed to remove ‘l4t/functions/acm.GS0/’: No such file or directory
Jan 28 23:58:23 localhost nv-l4t-usb-device-mode-stop.sh[4461]: l4tbr0: ERROR while getting interface flags: No such device
Jan 28 23:58:23 localhost nv-l4t-usb-device-mode-stop.sh[4461]: bridge l4tbr0 doesn’t exist; can’t delete it
Jan 28 23:58:26 localhost systemd[1]: nv-l4t-usb-device-mode.service: Failed with result ‘exit-code’.
Jan 28 23:58:26 localhost systemd[1]: Failed to start Configure USB flashing port for device mode.

This looks like a duplicate of another thread. My guess is here:
https://forums.developer.nvidia.com/t/jetson-agx-failed-to-start-configure-usb-flashing-port-for-device-mode/129612/3