Gigaset GS290 can't update to v0.16

Hi,
similar issue here. Just one release step later (0.16 to the new 0.17).

I got currently 0.16 installed on the device (according to GS290 /e/ Systemupdates Menu).
On offer for install (and already downloaded) is 0.17.
When I choose to install, I end up eventually on a recovery screen, where I can choose to

  • Reboot
  • Apply Update
  • Factory Reset
  • Advanced

with a terminal output below that says:
Finding update package…
Opening update package…
Verifying update package…
E: failed to verify whole-file signatue
Update package verification took 6.2 s (rersult 1)
E: Signature verification failed
E: error 21
Installation aborted
Install completed with status 1.
Installation aborted.

I guess choosing Apply Update would bring me to the same point again,
but I didn’t dare to and choose Reboot instead.

Any advise for this one?

Thanks,
Marcel