No grub after Windows 10 upgrade

i dualboot with windows10 and manjaro.
after the latest upgrade, grub vanished and all i can do is boot into windows.

What i did next:
i create a live medium from my old iso of manjaro., followed one of the threads to chroot into the system and update grub.

atleast i felt manjaro grub will be installed [without windows entry showing up] but no… grub failed to show.

sda stats…
sda1 : EFI
sda2: recovery partition
sda10: /
sda11: /home

i find a sda9 with 2g… [found nothing there !]
i mount /dev/sda10 in /mnt [usb], check the boot folder, it contains entries of manjaro. further there are 2 more folders grub and efi.
efi folder is empty, grub folder has files.

any clue how to get back on manjaro without re-install ?

This might help?

Use this or this. in uefi boot mode.

Since efi folder is empty, use configfile method (not chainloader).

Remember after booting up to Manjaro installed OS,
check if /efi/boot is mounted by 'findmnt /boot/efi’
And proceed with

sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck --debu
sudo update-grub

in my case, grub vanished, its windows boot [i am using dell inspiron, dual boot]


I booted of usb, chroot to respective partitions…

/dev/sda9 [a fat32 partition needed for efi system, usually 512 MB to 1G size] mounted to /mnt/boot/efi
/dev/sda10 [root file system for manjaro, i do not use /boot seperate partition]

one important issue, dont forget to load module efivars and then mount by issuing command as below

sudo mount -t efivars efivars /sys/firmware/efi/efivars

then i followed with command
sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck

finally i updated grub.

viola, after restart, i was able to boot into manjaro as grub showed up, but no windows listing… i still booted into manjaro, and opened terminal to update-grub.
this way os-prober worked and listed windows.

now i can happily dual boot as before !

thanks for clues :slight_smile:

That’s because you did not boot media in uefi.

i did issue the mount command and… i did boot off the usb UEFI mode. thanks again…