After recent update of nVidia drivers to 390.77 on Ubuntu 18.04 my external display stopped working. Is there some way to fix it (check X config/etc.) or at least to rollback to previous minor version of drivers (was 390.66 or something similar)? xrandr shows only internal screen.

Lenovo ThinkPad P50, nVidia Quadro M1000M
Ubuntu 18.04 (4.15.0-36-generic), nvidia 390.77