boot into something, figure out your partitions and chroot over to the fedora 39 root (with everything bound right) and do grub-install /dev/your_boot_partition after making sure the config is how you want it.
you can also boot the install media and skip to the bootloader section and only do that part. i used to do that when i didn’t understand how to diagnose and fix grub/lilo problems. sometimes it works.
boot into something, figure out your partitions and chroot over to the fedora 39 root (with everything bound right) and do grub-install /dev/your_boot_partition after making sure the config is how you want it.
Here’s the fedora docs on grub and here’s a stack exchange post where someone doesn’t succeed at it because they don’t troubleshoot their failed grub install. sad!
you can also boot the install media and skip to the bootloader section and only do that part. i used to do that when i didn’t understand how to diagnose and fix grub/lilo problems. sometimes it works.