LTE-Modem Firmware Upgrade on rbsxtr&r11e-4g

I’m reffering to this particular topic: http://forum.mikrotik.com/t/wap-lte-kit-lte1-interface-does-not-register-to-austrian-a1-network-static-ip-apn/115283/1

I experienced the same problem - when changing my location (so the modem uses another transmitter tower) it wouldn’t connect.
After turning the router on at the original location, it connected immediately.

My device is a RBSXTR&R11e-4g LTE-Router.

I tried upgrading the LTE-Modem firmware using the tutorial in the reffered topic, where I’ve only been kind of successful. After some research, I noticed that there’s a new “firmware-upgrade” command (/interface lte firmware-upgrade lte1 upgrade=yes). Before using the new command, I tried upgrading the firmware using AT commands but I always got an “operation not supported” error replied.

After I ran the firmware-upgrade command, I managed to upgrade the modem from firmware version v005 to v007. Unfortunately I at least will need version v008 to solve this problem.

Do you have any ideas how to solve this?

Best regards,
Benedikt