I’m adding this before my initial posted reponse, as I may have misinterpreted the context of your question:
When adding Linux to create a multiboot with an already-installed Windows, it is recommended to first disconnect the Windows disk before installing Linux to a second disk; to ensure that Linux does not mess with your Windows installation during install.
Multiboot Windows and Linux on separate disks
- Shutdown, turn off, and unplug your computer.
- Disconnect the Windows disk.
- Plug in the power again.
- Boot with the respective Linux Installer (Manjaro).
- Install and configure Linux (Manjaro).
- Shutdown, turn off, and unplug your computer.
- Reconnect the Windows disk.
- Plug in the power again.
- Boot to your BIOS and select Linux as the first boot option.
- Reboot, and enjoy.
This will allow Grub to become your prime bootloader for both Windows and Manjaro. If extra convenience or simplicity is desired, consider adding rEFInd UEFI bootloader, as mentioned below.
Important: Next time you boot into Windows
- Disable Fast Startup (if enabled).
This can be done from an administrative command prompt:
powercfg /h off
Add rEFInd for easier multibooting:
You have two ESPs; one for Windows, one for Manjaro, with each on a separate disk. This is an ideal scenario for multibooting.
I suggest adding rEFInd into the mix, which will allow you to boot both Windows and Manjaro. Neither the Windows or Linux bootloaders are harmed by installing rEFInd; they are still usable directly from rEFInd.
rEFInd will detect the Windows bootloader, the Grub bootloader, and allows you to bypass Grub if desired, by booting the Linux kernel stub directly. This is handy if Grub fails to boot, as you can still boot into Manjaro and repair your Grub in relative comfort.
rEFInd is a graphical bootloader which allows customising with many themes available from Github sites and other locations.
So, to recap, rEFInd will give you these choices by default:
- Windows
- Manjaro (Grub)
- Manjaro (Kernel)
(the naming will be different, but this gives a general idea)
The best way to see rEFInd in action is to use PACMAN and install it from the official Manjaro repos:
sudo pacman -S refind
This should automatically install rEFInd to its own folder on the Manjaro disk ESP. Reboot when finished installing. If it doesn’t boot into rEFInd the first time (it usually does), then reboot into your BIOS and make sure 'rEFInd UEFI bootloader` is the first in boot priority.
I hope this helps. Cheers.
A quick internet search revealed many themes. Here are two: