Comment 5 for bug 972294

I can confirm this bug with the same machine: non-native resolution and flickering, after installing the beta2 this morning.

A workaround for installation is to resort to the alternate-CD. Rebooting after finishing installion ends in black screen, but changing then into a console w/ CTL+ALT+F1 and restarting lightdm (sudo service lightdm restart) makes login screen accessible. Choosing there 2D-Desktop opens the Unity desktop, without "artifacts", but with the wrong resolution and the slight flickering already reported by @Svante. gnome-settings-daemon does not provide other resolutions.

By the way, adding "console=tty1" to grub default options does not resolve the problem, neither updating all the packages at their last version.

I keep investigating just in case, though kernel freeze is already done.