New Laptop but after Install no BIOS /UEFI /USB Boot possible anymore

[shaunakhub]

Have you tried this?

[HowTo] Boot Manjaro ISO directly with GRUB

Difficulty: ★☆☆☆☆ We are all familiar with burning live usb stick to boot our Manjaro isos. That is useful when you are installing manjaro on a new machine. However, if you already have linux installed with grub, there is a better way to boot Manjaro iso files. I usually do this when I test new iso files for a new release or when I need to use a rescue system because one of my experiments rendered my installation unbootable. You can boot the .iso file directly from your hard drive without burn…

It only needs an editor which is already there in grub rescue