Rock 3C dont boot up anymore

Hi!

Bought a Rock 3 Model C some weeks ago.
Yesterday I installed rock-3c_debian_bullseye_cli_b33.img.xz , configured some stuff, rebooted, all was fine.
Made an apt-get update and apt-get upgrade … looked good so far but somewhere at the end (after approx. 30 minutes) “updateing man db …” it hung. Tried to login via another SSH session, but wasn’t reachable anymore (also no ping).

Tried to reboot, but don’t reboot anymore. Green LED stays on, no blue LED.
Tried to re-image via a fresh SDHC image, but still the same.
Green LED stays on, no blue LED. Also Power-Button do NOT work (short nor >6 second long press).

Anything I can do?