Manjaro installation: Cannot establish Dual boot system - continued

[soundofthunder]

@jolexin

With these settings I booted Manjaro from the stick and invoked the Manjaro installallation program. The result is a Manjaro system on my hard disk that - hopefully - boots in UEFI mode.

It’s difficult to progress without knowing whether Manjaro is actually installed in UEFI mode or not.

• Did you recreate the Manjaro Installer USB to ensure that it boots in UEFI mode? The methods to do this vary depending on the method you used to create the USB.
• Did you subsequently install Manjaro in UEFI mode? Complications may arise if you failed to prepare your disk with a GUID partition table (GPT). In Calamares, before you choose a partitioning method, whether the disk and system is configured as UEFI (or not) is noted at the top of the screen (if you see MBR then it’s not UEFI).

@jolexin

After login to Windows I can invoke the “Settings” > “Windows recovery” > … > “use device” > “Manjaro”
Now the PC reboots and the GRUB menu appears. I can choose and boot Manjaro. Finally!

From that process I conclude that Manjaro is now installed in EFI mode. Is my conclusion correct?

If your BIOS also allows Legacy booting (i.e., CSM is enabled in a UEFI BIOS) this procedure can allow you to boot to Grub whether Manjaro is installed as UEFI or Legacy (but, after a forced reboot). So, this conclusion is indeterminate.

My assumption is that Manjaro is still booting as MBR.

@jolexin

I log into Manjaro. I run grub-instal to /dev/sda, I run grub-mkconfig -o /boot/grub/grub.cfg

Please boot to the Live environment of the Manjaro Installer USB, and follow relevant instructions in the following guide:

• Restore the GRUB Bootloader

Only follow directions intended for a EFI/GPT system. Naturally, the instructions rely on booting as UEFI; refer to information given in the previous thread; each OS must boot as UEFI.

Aside:- I wrote a general guide to multibooting Windows and Manjaro some time ago; I’ll link this here as it includes information which will also be beneficial (without actually following the guide).

• [Multiboot] Windows and Linux on Separate Disks

@jolexin

Ubuntu supports Secure Boot out of the box.
Arch/Manjaro can support it … but you must use self-signed keys, etc.

Yes, both of these comments are true, but are irrelevant to the issue at hand as Manjaro (by default) does not support Secure Boot, and thusly it should be disabled before installing Manjaro.

Note that disabling Secure Boot at the BIOS level (as you have done) is preferable to any mechanism Windows might offer.

@jolexin

I remember the boot priority of the startup screen (when I interrupted the boot process):

Boot mode: UEFI

Boot priority:

1. Windows xyz (Windows boot manager maybe?)
2. Windows
3. Windows

This appears that it might be a Windows generated screen; I can’t see with your eyes, so it’s difficult to be sure.

Changing the boot priority in BIOS to have Manjaro (or possibly ‘Linux OS’) appear first in the relevant section of the BIOS should ensure that Manjaro’s Grub UEFI bootloader boots first (which would then list Windows as an option).

If the Manjaro entry in BIOS is somehow missing, this can often be solved by following a guide such as Restore the GRUB bootloader (above).

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In the previous thread you mentioned:

When I boot Manjaro, I can look into the partitions. In the Manjaro partition I can see a directory /boot/grub with a grub.cfg file. In the EFI partition there is only Windows stuff, no hint of Manjaro or GRUB.

Is this still the case now?

• Yes – Manjaro is likely (still) booting in Legacy mode.
• No – Please show us exactly what you see.

If both Windows and Manjaro are installed using UEFI mode (no CSM) then the $ESP should contain these (top level) directories:

[ESP] -- BOOT
         Manjaro
         Microsoft

If the ‘Manjaro’ directory doesn’t exist in the ESP, the likelihood is high that your installation remains as a msdos/mbr based installation.

Again, as before, each OS and the installation media must all be the same type; either UEFI/GPT or MSDOS/MBR (legacy). From what you have shown, Windows boots as UEFI/GPT, but for some reason Manjaro is not.

You ask us to please explain;
Perhaps it’s time for show and tell:

1. Please show us some system information; Boot to the Manjaro Live envionment of your Manjaro Installer USB, and provide the output of:

inxi --admin --verbosity=8 --filter --no-host --width

2. Boot into your system BIOS firmware and show us your settings – specifically for Secure Boot, UEFI and Legacy/CSM and Boot Priority. Use a camera, if needed, and post clearly images.