Dual Boot Help (Win10 and CentOS8)

Question

Please help me guys. I'm losing my mind trying to dual boot my machine.

Here is the specs of my machine:

• acer 4755g
• SSD for windows 10 and HDD for CentOS 8 (partition, not whole disk is used)

Problem:

• CentOS grub cannot detect windows 10 bootloader.

Here are the steps that I have done to correct it:

• Installed ntfs-3g and ran sudo grub2-mkconfig > /dev/null. It still does not see the windows boot loader. In fact, sudo grub2-mkconfig > /dev/null returns nothing.

• Also tried to manually add chainloder on grub, still nothing.

• os-prober does not return anything

Possible reason for the problem

• Windows 10 is installed using BIOS and CentOS is using UEFI

I'm just confused on how CentOS managed to install UEFI on my machine. I'm pretty sure that my machine only supports BIOS. Note: To make the bootable USB, I used rufus with the MBR option.

FINAL NOTE:

I think if I convert the bootloader of CentOS from UEFI to BIOS, this problem will be solved. But can it be converted and How?

Solution

Have you installed ntfs support? Here is what worked for me:

sudo yum install epel-release
sudo yum install ntfs-3g

Then make a copy of your grub configuration file: cd /boot/grub2

sudo cp grub.cfg grub.cfg.bak

and finally create a new grub configuration:

sudo grub2-mkconfig -o /boot/grub2/grub.cfg

Comments

[diode121]

When you say "it is NOT possible to install UEFI bootloader on BIOS-booted system", does that mean my machine can actually support UEFI?..I tried to install windows 10 on gpt/uefi but failed..Is there anyway I can force CentOS to install in bios legacy mode?

[Michael Shigorin]

I mean that if CentOS is installed in UEFI mode (there's /sys/firmware/efi/ directory on a booted system) then your system has UEFI firmware indeed; it can have BIOS mode support via CSM/Legacy mode (but newer hardware was to drop it eventually IIRC). You can boot CentOS installation media in BIOS mode if there are two boot manager records for the boot media or if you disable UEFI booting at all for that particular boot event at least. The links above have it all well covered :-)