Nova firmware update fails

Hi all,

I’m having problems to connect my Nova via NB IoT. I opened a thread about that a few days back (https://community.hologram.io/t/nb-iot-usa/3434).
As I got no reaction there, I thought I might give the new Firmware Version a try. Unfortunately I also ran into Problems with the updater.
The output of nova410update.py is the following:

You are about to update the UBlox firmware on your Nova R410 device.
Once you continue past this point do not power off the modem
or stop this utility before it has completed.
Note that this update may change some behavior of the modem
related to profile selection and LED blinking. See hologram
documentation for more information.
The update may take up to 25 minutes to apply
Do you wish to continue? (y/n) y
Confirming modem type
Checking current modem version
Got version L0.0.00.00.05.06,A.02.01
Sending file /home/smartag/Downloads/hologram-tools/novaupdate/fw/0201/L0506A0201-to-L0508A0204/0bb_stg1_pkg1_0m_L56A0201_to_L58A0204.bin
Writing file to serial port
Waiting for stage1 return code
Waiting for modem
Still waiting for modem to finish install. Do not unplug
File failed. Trying next one in set
Sending file /home/smartag/Downloads/hologram-tools/novaupdate/fw/0201/L0506A0201-to-L0508A0204/0bb_stg1_pkg2_4m_L56A0201_to_L58A0204.bin
Writing file to serial port
Waiting for stage1 return code
Waiting for modem
Still waiting for modem to finish install. Do not unplug
File failed. Trying next one in set
Sending file /home/smartag/Downloads/hologram-tools/novaupdate/fw/0201/L0506A0201-to-L0508A0204/0bb_stg1_pkg3_8m_L56A0201_to_L58A0204.bin
Writing file to serial port
Waiting for stage1 return code
Waiting for modem
Still waiting for modem to finish install. Do not unplug
File failed. Trying next one in set
Sending file /home/smartag/Downloads/hologram-tools/novaupdate/fw/0201/L0506A0201-to-L0508A0204/1bb_stg1_pkg1_0m_L56A0201_to_L58A0204.bin
Writing file to serial port
Waiting for stage1 return code
Waiting for modem
ERROR: (‘Unknown flag’, ‘55506b67’)

Maybe sb hit the same error flag and has an Idea what I can try?
Any help is appreciated.

Best regards
Dominik