gnome-shell not working after fisrt update

[geolab]

HI. my first sabayon installation. gnome on a 64 bit. I have a nvidia geforce 410m card adn gnome-shell works out of the box until I do my first update. After that, I reboot but no gnome-shell but only fallback mnode.
I tried nvidia-xconfig then reboot but still no luck
am I missing something important? what should I check? nvidia - settings is workin and this means the nvidia driver is in use but I can't get gnome-shell working.
can you help me?

[wolfden]

check the logs