Windows 10 doesn't appear in boot manager after dual-boot install

Greetings everyone!

I followed this tutorial but installed Manjaro XFCE on a dedicated hard drive. I ran two commands as seen in screenshot and can see the Windows drive. When I reboot my pc, it doesn't boot into GRUB nor does my Windows 10 installation appear in the UEFI. What is I'm doing wrong? BTW my UEFI is ASUS if thats any helpful. I'll be more than glad to post more info if needed. Screenshots below

Screenshot_2019-12-09_11-48-55

Judging by the free space on the efi partition I'd hazard to guess that you've over written the windows bootloader rather than installing grub alongside it. I'm guessing that fat32 is your efi partition? It's missing the boot and esp flags which is probably why it isn't booting.

That's my somewhat educated guess at what's gone wrong, unfortunately having only recently muddled through a multiboot install myself I'd rather not be the one to advise you on how to fix this. Fret not, it's probably just a case of changing the boot flags but best to wait until someone more experienced comes along. (there's a couple of resident boot experts floating around I'm sure.)

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For better readability/visibility, please copy the terminal output, paste it here, highlight it and use </> to format.

Now it seems that your Windows is installed in legacy/bios/mbr mode ad your Manjaro in UEFI. Though I don't understand why the fat32 partition on /dev/sda is flagged as msfdata. It should be esp,boot :thinking:

On the other hand you seem to have an EFI boot entry for Manjaro. Did you change the flag after installation?

Verify in what mode you are booting up Manjaro by running the following command:
test -d /sys/firmware/efi && echo UEFI || echo BIOS

Check also if you can boot into your Windows via bios boot menu. If so, I guess you would need to reinstall Manjaro in legacy mode. But wait for the confirmation from the experts on the forum.

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I missed that, saw ntfs and assumed they were just data partitions. Sometimes I forget that there was a time before uefi :sweat_smile:

No, I haven't changed a flag.

Attempted to boot via bios boot menu and Windows installation is not there. I than re-enabled secure boot, CSM and fast boot.... still nothing. So I resorted to deleting Manjaro and lo and behold, Windows 10 appeared.

I would share my existing setup on my Acer laptop.
I have installed manjaro along side with win10. But due to confusion in efi, i had created a separate efi partition and flagged.
Now if i Start laptop, i get to windows but when I hit F12 i get boot options to choose my OS.
No issues as long as i can boot into manjaro ...

Seems like the boot flags weren't set during installation then. Usually they're set automatically but it's easy enough to miss with a custom install. The mixing of partition tables is a whole other issue though, as I recall the dual booting guides all assume that the installs will be sharing the same disk under either legacy bios or uefi conditions, not both.

It is possible to install each os on a separate drive and choose which one you want to boot from via the bios. But imo it's easier to install Windows and Manjaro on the same drive and have them share an efi partition for booting. Windows updates are known to occassionly wipe Linux bootloader's but it's a 5 minute fix as long as you keep a live cd/usb handy.

The second disk can be used for data and can be accessed from both installations, whereas if you install Manjaro on the entirety of one of your drives then that drive can only be accessed from Manjaro, not ideal for dual booting.

Your Windows is installed in legacy mode.
Keep CSM enabled but disable secure and fast boot.
Boot up your Manjaro usb in legacy mode (in bios boot menu: the name of the vendor without any UEFI before it).
Create a new partiton table: msdos.
You wont be needing any EFI partition.
Partition the disk as you wish. (/, /home, swap).
Install Grub to the drive (/dev/sda/) and not to any particular partition.

Further to Marte's

o first partition
o unallocated
o size 1 MB
o labelled as 'bios-grub'

Easier to use gparted to do this.
Probably easiest to reinstall and make disk msdos first.

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