Please perform the steps described in the post below to rebuild the Grub environment:
Note that if you are on MBR/Legacy boot you need to adapt the step 6 to install the bootloader into MBR of your disk.
After reboot, if everything is well, uninstall Grub Customizer and remove the .old remains. Btw, if I remember correctly, MX Linux uses a modified Grub which can create a correct entry in grub.cfg for Arch-based systems so you could use that also, if you wish so, to boot your EnOS.
edit: typo, typo ![]()