Aha. In trying to use --reinstall, I ended up hitting another bug, #859188. On that bug, commenter Sal Mazzola (@salmaz) suggests using this alternative method to work around it:
apt-get download libgl1-mesa-glx libgl1-mesa-dri dpkg --install libgl1-mesa-*.deb I now have working GLX again! -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to fglrx-installer in Ubuntu. https://bugs.launchpad.net/bugs/855943 Title: Installing then uninstalling FGLRX makes Oneiric's Unity unbootable To manage notifications about this bug go to: https://bugs.launchpad.net/compiz-core/+bug/855943/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp