Updating Cosmic Mod
Update the passwords by pressing ctrl+alt+t to launch a terminal and use the command passwd to update the root password and passwd mod to update the user password.
The system can be updated via emerge --sync then you can do emerge --ask --verbose --update --deep --newuse --with-bdeps=y @world
Make sure to run emerge --depclean after a world update to keep your system clean.
If the kernel's sources are updated, point the symlink to the correct folder via the commands below adding in the kernel number you get from the list.
eselect kernel list
eselect kernel set