Reboot to black screen 'reboot and select proper boot device', cant reinstall GRUB

[Mirdarthos]

Perhaps this helps:

[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 change…