my Toshiba was initially a EFI-equipped 'safe boot' Windows 8 PC. it's now an all Ubuntu PC. it was a PAIN to ditch all that crap to get the live CD to boot but i found a trick online. when in Win8, go to the 'charm bar' as it is called, click 'settings' (gear on bottom) and where it says 'power', hold down your shift key, and while holding click 'power' and 'restart'. keep holding shift until you see a screen of choices, and click on the second option on the left side, it mentions something about booting a DVD, USB stick on it. it will reboot the machine. but the BIOS trick is the hard part. depending on the manufacturer it could be any number of the F keys or the delete button. i just randomly hit all of them and then a boot menu with the last option being edit system settings popped up. that got me into the BIOS, where i easily disabled both safe boot and EFI boot. when in the Ubuntu installer, i found out the EFI isn't the BIOS, but a separate hard disk partition with the volume label being EFI. blew all of them away and it was easy after that.
Samsung Galaxy S4 **NEW** (GS3 screen finally shattered)
Samsung Galaxy Tab 3 7.0 (non-rooted, stock)
Samsung Galaxy Tab 2 10.1 (obsolete, slow, rooted)
Samsung Galaxy Note 10.1 2014 Edition