As far as I know, removing the sim won't prevent the sms in the end (it will be send as soon as the sim is in?).

On the location where I am, there is no wifi. When I read and combine all, it seems that I need to upgrade: either through the updater under Windows or download the file and install manually under Linux, both without the sim. Manually create the file /home/user/.cherry_state and switch off/switch on (since reboot is not configured). When all goes well, repeat the procedure and insert the sim.