I solved it eventually, but forgot about this post. If I remember correctly I had to make a bootable pendrive with the 18.04 installer, because it wanted to modify something, and couldn't do it with live cd. And how I found this out is a mystery for me right now.
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1810200 Title: Can't install Ubuntu from live cd when nomodeset is added Status in linux package in Ubuntu: Expired Bug description: I'm having issue with nouveau. (Overheat. See Bug #1768976). To disable nouveau when using live cd I found, that I need to run the live Ubuntu with nomodeset. The live Ubuntu starts fine, no overheat, able to use every program on livecd, except the installation itself. No matter how many times I click on it, nothing happens. Same as with starting the just install option, installation app not starts. I tried with 18.04.1 and 18.10 live cds. Can I make this work with nomodeset? Maybe by adding an other option? Do you know other way to run livecd with disabled nouveau? To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1810200/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
