Recover manjaro after installing openSUSE

[cscs]

Manjaro needs manjaro’s grub unless you do some witchery.

Manjaros grub can boot everything else, but if you install another system and its grub as well, overwriting manjaros grub, then manjaro will struggle to boot.

You should probably follow one of the methods here:

[HowTo] Resolve an unbootable Manjaro (black screen, login failed, cant boot, etc)

When we have problems gaining access to our systems it is difficult to gather information, let alone fix any problems. Here we will cover common causes and solutions to ‘manjaro wont boot’. TTY If your desktop does not load properly then you might still be able to use most, if not all, functionality by dropping to a non-graphical TTY. By default your system will have multiple TTYs, with each corresponding to an Fx key. Your desktop is assigned to one as well - most often F1. You can chang…

Then you will need to reinstall and update grub.