While I know some facts about UEFI and Legacy and basic differences between them, like UEFI allowing for faster booting (I've checked this question already, but it doesn't answer mine), I have a bit of a different question(s):
I'm not sure if BIOS settings can have any influence on how the system works and if legacy settings can be the cause of hardware misbehaving, but I usually install my Linux systems in legacy mode, with boot priority legacy first. Is it ok this way or should I change either the boot priority to UEFI first, or everything adjusted to UEFI (this Lenovo G50-45 laptop came with Windows 8).
Also, on my laptop quite a few things don't work properly, whereas on Windows everything worked and I'm not sure where the fault lies. I only recall, that Windows wouldn't install with legacy settings, I had to change boot priority to UEFI first to be able to install it (Win 7 Ultimate x64).
Currently on *ubuntu (any variant) 15.04 I have issues with microphone not working (distorted, very weak sound) and Xorg crashes my entire session with Libreoffice in k3.19+. Tested with many distributions.
So, to conclude, which one is recommended for a flawlessly working system? Do Linux distributions work better with Legacy, or UEFI? (if there is any difference in terms of functionality of the system)
Best Answer
For most hardware, the boot mode (EFI vs. BIOS) is irrelevant. The drivers Linux loads are identical in either case, as should be the performance. The main caveat here is that the hardware may be initialized in different ways depending on your boot mode, and if the Linux drivers make assumptions about how the hardware is initialized, one way or the other may work better. This sometimes made booting one mode or the other (usually BIOS mode) preferable in the past, but this type of problem is becoming rather rare today. This type of issue mostly affected video hardware and drivers, but in principle it could affect anything.
In your specific case, my suspicion is that you've got "bleeding-edge" hardware with poor Linux support, or perhaps hardware that requires special configuration to work correctly in Linux. Your best bet is to post separate questions about each specific device that's not working to your satisfaction. You can also test with both BIOS-mode and EFI-mode installations to determine empirically which one works better for you, since there is no way to accurately generalize which mode is best.
The correct answer to the question of which mode is best is: It depends. For instance:
If you need a more specific "BIOS" or "EFI" answer as to which you should use, you'll have to provide much more specific information about your setup.