[ubuntu] installing ubuntu 12.04 on Mac Mini 4,1

Hello,

I am trying to install Ubuntu 12.04 on MacMini 4,1 (model with Nvidia graphic chipset) from an USB drive. When I select "Try Ubuntu Without Installing", the OS will boot but end up in strange graphic mode with strips over the upper part of the screen.

I managed to install 10.10 by setting boot parameters to "nomodeset reboot=pci" but this doesn't work with 12.04 anymore.

I went through several posts and have tried various options e.g. "nomodeset xforcevesa" or "blacklist=vga16fb" with no luck. Adding the "nomodeset" option makes the starting screen to show up but then it switches to a text console.

Any hints appreciated.

Regards,
Jan