Impossible to install Ubuntu 13.04

Impossible to install Ubuntu 13.04

I know there are many questions like this but didn't found any answer.
I'm trying to install Ubuntu 13.04 on my Toshiba c855-233 alongside
Windows 8.
It has UEFI and SecureBoot (the latter can be disabled but it ends with
the same result).
I tried with two different USB flash drives and the result is the same.
I set up the bios to boot from USB and I directly get to the grub menu, it
never shows options about UEFI
For example something like this is never shown:
That as mentioned here (Installing Ubuntu on a Pre-Installed Windows 8
(64-bit) System (UEFI Supported)) should be shwon on boot.
Instead I get directly to the Grub options, and whatever I select I get
something similar to that (with the screen flashing): .
I think, but I have no clue, that t may be a graphic problem since in the
flashing screen a really small strip in the top of the screen seems to be
"working" (not flashing).
The graphic card is an AMD Radeon™ HD 7610M Graphics (1GB dedicated memory).