Default GRUB boot entry not working.

[CaffeineAddict]

a regular distribution and an Atomic distribution

What the heck is "atomic" distro lol
Why do people even bother with things that need special care especially if it's something non standard.

 

[f33dm3bits]

What the heck is "atomic" distro lol
Why do people even bother with things that need special care especially if it's something non standard.

Atomic aka Immutable distributions, they're imaged based Linux distributions focused on a containerized workflows, but dual-booting with those doesn't seem to be very well supported as with the warnings that they have limitations when it comes to custom partitioning and dual-booting.

Fedora Atomic Desktops User Guide

Learn more about Fedora Linux, the Fedora Project & the Fedora Community.

docs.fedoraproject.org