[ubuntu] Strange image with splash screen (plymouth)

Spalsh.jpg
Hi.

I installed Ubuntu 12.04.3 (actually, with a Dream Studio tweak on it afterwords) on my wife's Macbook 5,2. Everything is great, but the splash screen appears like if there was a problem with the screen. Please take a look at the picture I attach.

I tried with the default (DreamStudio and Ubuntu) plymouth themes, and it's always like this. Actually, it was already like this with the live usb stick.

It must be a problem of the driver with plymouth, or grub, or.. I don't know. Everything else, graphically speaking, is fine (the login screen is perfect, and the rest too, of course).

Any help, please?

Thanks

Attached Images

• Spalsh.jpg (50.5 KB)