After I upgraded to Ubuntu 11.04 I couldn't boot my system. After grub I had only a screwed up screen. I tried with a USB pendrive with Ubuntu 11.04 installed, just a black screen. I was helped and now I know the problem is that I need to set the nomodeset parameter when booting. This way I can boot both my system with the 2.6.38 and from USB.
Does anybody know why this may be happening? I'm using an ATI with opensource drivers. Kernel 2.6.35 is still working correctly. Maybe this sould be reported?
I read what nomodeset is used for, and it is not completely clear to me. Anyone who can try to explain it and its relation to graphics drivers?