Pre-question information:
I have:
ASUS P8 Z77-V LX Motherboard
(running BIOS Setup: ASUS UEFI BIOS Utility v. 1201 x64)
2x Empty HDDs:
1x 3TB
1x 1TB
A lot of time
Aim
I'm wanting to Dual boot Windows 10 with Ubuntu Studio 16.04 in UEFI mode (Legacy BIOS is out of the question). I have installation discs of both.
What I've done so far
With no HDDs attached, booted BIOS and disabled CSM (to force UEFI mode).
I plugged in and, using GPT, partitioned & formatted my 3TB HDD then installed Windows 10. I can tell it was successful in installing Windows 10 in UEFI mode as when I run msconfig32 it states the BIOS mode is UEFI.
I then shutdown my PC, unplugged my 3TB, plugged in my 1TB, put in my Ubuntu Studio 16.04 Live disc and booted.
For the sake of providing information if it's related, to successfully install Ubuntu studio I had to:
Edit the menu option "Install Ubuntu Studio" to include nomodeset
and nolapic before running to ensure UI actually loaded.
Disable Ethernet Network connection on the installation setup desktop.
Leave "Download updates" and "Install 3rd Party Applications" unchecked.
Steps 2 and 3 were required due a bug in the installation process where the "Force UEFI mode" warning box would not close on clicking Continue. For some reason, performing steps 2 and 3 nullified this issue.
I formatted my 1TB drive using GPT and making the following partitions:
1000MB EFI System Partition (ESP) (I know 1GB is over kill, but space isn't a problem for me)
128000MB Ext4 partition mounting at point /
16000MB Swap space
All remaining space (~800GB) as an Ext4 partition mounting at point /home
The installation process seemed to be successful, however upon rebooting my PC, my motherboard/firmware refuses to load Ubuntu studio and states:
The current BIOS setting do not fully support the boot device.
Click OK to enter the BIOS Setup.
Go to Advanced > Boot > CSM Parameters, and adjust the CSM (Compatibility Support Module) settings to enable the boot device.
I don't want to do that.
I tried it (enabling CSM) and it booted Ubuntu Studio...into BIOS mode. I check this by performing:
and it stated BIOS.
I don't get why it's only booting to BIOS mode if I installed it in UEFI mode, clicked Continue on the "Force UEFI mode" warning, and it has a ESP which when I booted (in BIOS mode) stated that it mounted at point /boot/efi and had the boot flag.
I have shutdown and disabled CSM, disabled "Fast Boot" after I realised that it was enabled, checked that "Secure Boot" is disabled (it is) and now I'm stuck as to what to do next.
What should I do?
Some quick proof I've done things correctly:
Ubuntu is partitioned correctly:
Warning message on startup:
Boot Priority doesn't even recognise the drive: