Re: problem installing grub to linux mint partition

[David H. Durgee]

> Le 03/06/2018 à 15:11, David H. Durgee a écrit :
>
>         Le 03/06/2018 à 02:24, David H. Durgee a écrit :
>
>             I am encountering problems attempting to install grub on a linux 
> mint 18.3 (sylvia) partition on a multi-boot system.  When booting the live DVD 
> and invoking its installer the partition is not listed as a target to install 
> grub.
>
>
>         Which devices are listed ?
>
>
>     The only partitions listed as possible grub targets were the master boot record, a FreeDOS partition and two NTFS formatted Windows partitions. The JFS formatted linux and eCS partitions, including the target for the new installation, were not listed as possible grub targets. 
>
>
> Could the first three partitions be primary partitions and the other ones be 
> logical partitions ? Then the Mint installer may consider that there is no 
> point in installing GRUB in a logical partition PBR, as it cannot be booted 
> from a standard MBR (however it can still be chainloaded from another boot 
> loader).
>
>
>     You are correct, I ran grub-install and grub-probe in a terminal window started from the Live DVD session.  I have NOT installed sylvia yet, so chrooting is not an option at this point.  Given I cannot select the proper target for the grub install I aborted the install itself. 
>
>
> Do you mean that the Mint installer offers to install GRUB before installing 
> the base system ? Weird.


I don't believe it actually installs grub at that point, it simply wants 
to know where it should put it.


>     I had not thought that grub-probe error related to the source instead of the target. 
>
>
> The error is not related to the source. The /boot directory is a target too.
>
> The GRUB for BIOS boot loader installed by grub-install is divided in three 
> parts : 1 - the boot image is installed in a disk (MBR) or a partition (PBR) 
> boot sector 2 - the core image is installed on the same drive as the boot 
> record ; the exact location can vary and is selected automatically by 
> grub-install, you do not have direct control over it 3 - modules, config files, 
> fonts, language files... are installed in the /boot/grub directory or 
> ${boot-directory}/grub if specified ; it can be on a different drive.
>
>
> grub-install must be able to map these locations to "real" drives, because they 
> must be readable using disk BIOS calls (int13h) at boot time. You get the error because 
> the current /boot is included in a AUFS filesystem which cannot be mapped to a real 
> drive. Anyway, this would be the wrong location. You want /boot in /dev/sda15, not in the 
> installer's virtual root filesystem.
>
>
>     Can you confirm for me that JFS is a supported grub install target?
>
>
> No, because I do not use JFS. But I wonder why GRUB would drop support for JFS 
> and I can see that the current development GRUB packages in Debian still 
> include the jfs module.
>
>
> <https://packages.debian.org/sid/amd64/grub-pc-bin/filelist>

In that case perhaps it is the mint installer that is excluding JFS targets.


>     I can see from the targets listed that FAT and NTFS are supported, but obviously I am not going to install linux on either of those. 
>
>
> Note that installing GRUB's boot image on a given target device does not 
> require that GRUB fully supports its filesystem. The only requirement is that 
> GRUB know that the boot sector format leaves enough available space to install 
> the boot image. GRUB must only support the filesystem containing /boot, because 
> this is where GRUB files and kernel files are located.

I received a suggestion on the mint forums that pointed me to a way to 
install sylvia without it installing the boot loader.  Were I to do so 
would it work for me to then chroot /dev/sda15 and run grub-install 
there?  Or would things be a bit more involved than that?

Dave