I don't know. Because 1st time i want to install Ubuntu 12.04 in my 530U3C, the laptop always boot to windows even if i set the 1st boot priority to "USB HD". After that i tried to boot normally and press F10 to show the boot options, the boot options appeared but there is no USB option in it. So i tried to enable the EFI boot options and press F10 once again... Viola the boot options appeared and i can boot from USB.
In the 2nd attempt all i do is enable the EFI boot options - reboot - press F10
Sorry for my bad english.