Bug 25195

Summary:	Installer advertises about chainloading, but this is not possible with standard installation
Product:	Mageia	Reporter:	papoteur <yvesbrungard>
Component:	Installer	Assignee:	Mageia tools maintainers <mageiatools>
Status:	NEW ---	QA Contact:
Severity:	enhancement
Priority:	Low	CC:	jasperodus, mageia
Version:	Cauldron
Target Milestone:	---
Hardware:	All
OS:	Linux
See Also:	https://bugs.mageia.org/show_bug.cgi?id=18761
Whiteboard:
Source RPM:		CVE:
Status comment:

Description papoteur 2019-07-29 08:38:24 CEST

Description of problem:
According to #18761, Grub is no more written in the Partition Boot Record. Thus, for what I understand, Grub can't be chainloaded from another bootloader.
However, when option "Don't touch MBR or ESP" is choosen, a warning says:
"Not installing boot loader on ESP or MBR means that the installation is not bootable unless chainloaded from another OS." 
The only way for booting Mageia just installed is to use Grub from another system an that it detects Mageia as "Foreign OS". Is it true?
I propose that the warning would be amended accordingly.
Version-Release number of selected component (if applicable): Mageia 7 and 7.1

I propose too to adapt the documentation with this:

Do not touch ESP or MBR

Select this option if you don't want a bootable Mageia, but would rather boot it from another bootloader.
Warning: As any bootloader can't be written in partition boot record, this installation has to be detected from another bootloader like Grub to be booted. Classic chainloading is not available.
You will get a warning that the bootloader is missing. Click Ok if you are sure you understand the implications, and wish to proceed.

papoteur 2019-07-29 08:40:02 CEST

See Also: (none) => https://bugs.mageia.org/show_bug.cgi?id=18761

Comment 1 Lewis Smith 2019-07-30 21:17:19 CEST

Papoteur
Are you talking MBR? I used to put Grub on root partitions, and chainload them from whatever the MBR loaded. Is this what you want to do?
On an EFI system, rEFInd will, if you have it (you should), independently boot anything on the system. Otherwise, allowing normal Grub2[efi] installation, will boot the most recently installed Mageia, whose boot menu should show all other installed systemss.

Your proposed re-wording of the 'no bootloader' warning is debatable. Let the ISObuild team reply.

Assignee: bugsquad => isobuild
Severity: normal => enhancement
Priority: Normal => Low

Comment 2 Antony Baker 2019-08-01 18:19:56 CEST

Is this what you are highlighting Papoteur:

For the Installer warning pop-up to say that if "Don't touch MBR or ESP" is choosen you will then not be able to boot *unless* via chain-loading from another OS is not strictly true - as you potentially could employ the Probe Foreign OS method.

-------

Regarding chain-loading itself, if I have understood the situation correctly, GRUB2 & rEFInd work, and are supported by Mageia. As such, I have had a go at the documentation - and slanted it according to my assumptions above ...

"Chain-loading via legacy bootloaders (GRUB Legacy and LiLo) is no longer supported by Mageia as it is likely to fail when attempting to boot this resulting installation of Mageia. If you use anything other than GRUB2 or rEFInd for this purpose, then you do so at your own risk!"

Is this correct/acceptable for the documentation side of things?

Antony.

CC: (none) => jasperodus

Martin Whitaker 2019-08-04 23:42:45 CEST

CC: (none) => mageia
Assignee: isobuild => mageiatools

Comment 3 Antony Baker 2019-08-04 23:57:06 CEST

(In reply to Antony Baker from comment #2)
> 
> "Chain-loading via legacy bootloaders (GRUB Legacy and LiLo) is no longer
> supported by Mageia as it is likely to fail when attempting to boot this
> resulting installation of Mageia. If you use anything other than GRUB2 or
> rEFInd for this purpose, then you do so at your own risk!"
> 
Just to be clear, when I say:
> Is this correct/acceptable for the documentation side of things?
I mean for the text in the manual - not for the installer pop-up warning.

Antony.