I booted an ubuntu liveCD to rescue my system and so far I'm angry.
Like the upgrade bricking my system made me sad and blue.
Now I booted xubuntu live CD thinking it's the flavor I installed so it might work better. I see no option beside install and nuke all data in disk. No rescue button, nothing. Mounting my partition doesn't work because the liveCD can't mount partition of type crypto_LUKS. Starting firefox on the liveCD required me to click 3 skip buttons.