Dual Boot Windows 10 & Linux

Configuration required in any system with Windows 10 preinstalled before installing Linux


Our goal is to install Linux alongside with Windows 10. A dual boot system will let us choose between this two Systems at the start. Our system came with Windows 10 preinstalled. Basically the idea is that Windows has the control over the drive even when it is switched off so some configuration needs to be done before installing Linux in order to be able to share the drive with Linux. These are Turn Off Fast Start, Turn Off Secure Boot and Switch from RAID to AHCI.

The access key to access to the BIOS Setup and Boot Menu is usually different between systems. In Dell System it is F2 and F12 respectively.

Create a Recovery Drive

It is a great idea start creating a recovery drive of our system. Windows Create Recovery Drive

Turn Off Secure Boot

Enter BIOS Setup (in my system is F2 but can be different).

Look for Secure Boot option and uncheck.

Secure Boot

Turn Off Fast Startup

Power & sleep options → Related settings. Additional power settings. → Choose what the power buttons do → Change setting that are currently unavailable → ( uncheck ) Turn on fast start up (recommended)

Fast Startup

Disable Hibernate

Command prompt as administrator ( type cmd in start field, right click on Command Prompt entry an click “run as administrator”)

c:\ > powercfg -h off

In the screen given above, into section “on baterry/Plugged in” “hibernate” has not to be selected.

Save changes, close and restart.

Switch Windows 10 From RAID To AHCI

Thanks to this very easy way, we can do this without reinstalling Windows 10.

With RAID ON, the Linux Installer or Linux Live does not detect our HDD or SSD so the only option is to install Linux on a USB memory stick. We have to change our SATA configuration from RAID to AHCI.
In a command prompt as administrator type:

bcdedit /set {current} safeboot minimal

If this command does not work try without {current}

Restart and enter BIOS Setup (in my system is F2 but can be different). Change the SATA Operation Mode to AHCI from RAID ON.

AHCI

Save Changes & Exit.

Our system will start in Safe Mode. In a terminal as administrator, type:

bcdedit /deletevalue {current} safeboot

or without {current} if the first command does not work.

Reboot Windows, and our HDD is in AHCI mode, our Linux installer will detect this drive and the Windows installed on it.

Configure GRUB2 After Instalation

We can easily configure the boot menu.

For example, if we want to change the timeout, the default entry and the resolution of the menu.

In a terminal and as administrator edit (which the inline editor ‘vi’, for example) the file “/etc/default/grub” which is the configuration file of GRUB2.

GRUB_DEFAULT = 0, number line of default boot.
GRUB_TIMEOUT=5, time to wait until default boot.

Change resolution:

Choose a resolution: in the boot menu, type ‘c’, and access to grub terminal, here type the command “vbeinfo” that actually seems to be “videoinfo”, this command gives us the resolutions that GRUB recognize.

In the file given above uncomment the line GRUB_GFXMODE and change the resolution.

Dual Boot