Hai all,
I’ve installed fedora 36 pre-release a week ago. But this is surprise to me because all my other os linux in my laptop detected and add entry to grub by fedora 36 prerelease installation.
Actually before I Installed fedora 36 prerelease, I had 3 OS installed, windows 7, Kali linux, and ParrotOS. if I update or upgrade system in example kai linux, kali linux also generated grub so, grub generated by parrotos replaced. so if i want to boot into parrotos i use disk boot repair and it works but only detect and add to grub menu bootloader parrotos and windows 7, and also when i want to boot into kali linux i use disk boot repair and only kali linux and windows 7 detected and add to grub menu bootloader.
But after I installed fedora 36 prerelease I surprised because fedora can detect all my OS in my laptop and add all entry to grub menu bootlaoder. See SS below.
The question is, what exactly command to generate grub so the result is like in my SS?, I know i can use chroot with fedora live usb if for example I boot into parrotos and update/upgrade then parrotos replace grub menu bootloader with it version?
Yes, I am surprised, because sometimes after use disk boot repair, in example i choose to boot kali linux, disk boot repair don’t to repair grub perfectly, windows 7 partition it’s not detected. Then usually i do grub-install target=i386-pc /dev/sda then I do update-grub. Windows is detected and add to menu grub bootloader. but ParrotOS is not detected. I surprised in this, fedora 36 pre-release installer can detect all my os in my laptop perfectly. I curious if i boot to parrotOS (parrotOS release new version) then i do sudo parrot-upgrade. automatically upgrade generated grub with it version, because kernel is updated. I predict and sure(base on my experience) parrotOs cannot detect my fedora, kali linux, so because of this I want to know what is exactly command in fedora 36 pre-release so i can replace those grub menu with grub bootloader fedora, and I can access all my os again perfectly?. I plan to recovery grub fedora with usb live fedora then do chroot.
I think it likely that if you allow any grub but fedora to update the boot loader you will be back to what you had before.
Alternatively you can update the other os, then boot back to fedora and update grub there with the manual sudo grub2-mkconfig -o /etc/grub2.cfg it will restore the fedora boot loader and you should then be able to boot to any of the 4 OSes from there. That may require you to boot from a live usb device then chroot to the fedora install so it can do the job properly but should work.
This new grub update also have some better ability to detect other OS and for this reason I disabled it since I prefer using efibootmgr by changing the boot order (UEFI).
May be from above it also advancing the grub detection with legacy BIOS. I think in the past when legacy BIOS still common, we could also create dual booting (Ubuntu & Windows).
The OP is using MBR boot so efibootmgr is not likely to have any affect for him. As I recall, when using legacy boot the MBR was only able to boot one OS and grub had to manage everything else. Thus if grub did not provide the menu to select other OSes to boot you were stuck.
Thanks you very much for fedora developer, I’ve update/upgrade kali linux and parrot os to the lastest kernel, I also update fedora 36 beta to the lastest kernel, and amazing I don’t need worry about Grub menu loader, because kali linux dan parrot os can update entry in grub menu bootloader fedora but won’t replace it. This problem solved. Kali linux and parrot os update/upgrade successfully but won’t replace fedora 36 beta grub menu bootloader. No matter what I update first,
