https://wiki.manjaro.org/index.php/Restore_the_GRUB_Bootloader#Use_mhwd-chroot
create manjaro usb and boot on it
open terminal and mount hard drive. In my case, it was:
sudo mount /dev/nvme0n1p2 /mnt
chroot to hard drive (taking care of mount binds):
manjaro-chroot /mnt /bin/bash
reinstall old package from pacman cache:
pacman -U /var/cache/pacman/pkg/linux49-4.9.105-1-x86_64.pkg.tar.xz
exit chroot, unmount /mnt and reboot