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How to install GRUB on removable media?

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  How to install GRUB on removable media? Robert Latest <boblatest@yahoo.com> - 2021-09-14 19:44 +0000
    Re: How to install GRUB on removable media? Robert Latest <boblatest@yahoo.com> - 2021-09-14 19:51 +0000
    Re: How to install GRUB on removable media? Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-09-15 08:15 +0200
    Re: How to install GRUB on removable media? "Carlos E. R." <robin_listas@es.invalid> - 2021-09-15 13:59 +0200
      Re: How to install GRUB on removable media? Pascal Hambourg <pascal@plouf.fr.eu.org> - 2021-09-15 14:54 +0200
        Re: How to install GRUB on removable media? "Carlos E. R." <robin_listas@es.invalid> - 2021-09-15 16:21 +0200
          Re: How to install GRUB on removable media? "Andrei Z." <no-email@invalid.invalid> - 2021-09-15 18:04 +0300
          Re: How to install GRUB on removable media? not@telling.you.invalid (Computer Nerd Kev) - 2021-09-15 22:20 +0000

#33211 — How to install GRUB on removable media?

Hi all,

I have this company Windows laptop that I use privately by booting from a USB3
SSD with a Debian installation. This used to work for years until it didn't any
more a few days ago. Anyway, I ended up re-installing the complete Debian onto
the same SSD again. However, I cannot figure out for the life of me how to make
the thing bootable. The SDD usually shows up as /dev/sdc and has three
partitions: /dev/sdc1 doesn't matter, /dev/sdc2 always was mounted under /boot,
and /dev/sdc3 is the root device.


In order to get the thing running I boot from the Debian install USB stick,
mount /dev/sdc3 under /mnt, do the mount --bind thing for /proc, /sys, /dev,
and chroot into /mnt.

/dev/sdc2 is EFI type "ef", and formatted as FAT and mounted at /boot (in the
chrooted environment). I also made a /boot/grub/efi directory.

But I can't install grub: 

# grub-install
Installing for x86_64-efi platform
grub-install: error: cannot find EFI directory.

I've searched the Net up and down for this error message but couldn't find any
hint on how to deal with it.

Or maybe it isn't possible to use EFI on removable media? Do I have to install
it in the MBR? My knowledge about this is extremely shaky.

Thanks!

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#33212

Robert Latest wrote:
> Hi all,
>
> I have this company Windows laptop that I use privately by booting from a
> USB3 SSD with a Debian installation. This used to work for years until it
> didn't any more a few days ago. Anyway, I ended up re-installing the complete
> Debian onto the same SSD again. However, I cannot figure out for the life of
> me how to make the thing bootable. The SDD usually shows up as /dev/sdc and
> has three partitions: /dev/sdc1 doesn't matter, /dev/sdc2 always was mounted
> under /boot, and /dev/sdc3 is the root device.
>
>
> In order to get the thing running I boot from the Debian install USB stick,
> mount /dev/sdc3 under /mnt, do the mount --bind thing for /proc, /sys, /dev,
> and chroot into /mnt.
>
> /dev/sdc2 is EFI type "ef", and formatted as FAT and mounted at /boot (in the
> chrooted environment). I also made a /boot/grub/efi directory.
>
> But I can't install grub: 
>
> # grub-install Installing for x86_64-efi platform grub-install: error: cannot
> find EFI directory.
>
> I've searched the Net up and down for this error message but couldn't find
> any hint on how to deal with it.
>
> Or maybe it isn't possible to use EFI on removable media? Do I have to
> install it in the MBR? My knowledge about this is extremely shaky.
>
> Thanks!

Note, I also tried grub-install --efi-directory=/boot/efi, same result.

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#33214

Le 14/09/2021 à 21:44, Robert Latest a écrit :
> 
> /dev/sdc2 is EFI type "ef", and formatted as FAT and mounted at /boot (in the
> chrooted environment). I also made a /boot/grub/efi directory.

For GRUB the EFI partition must be mounted on /boot/efi, not /boot.

> But I can't install grub:
> 
> # grub-install

To install GRUB on a removable media you should use

# grub-install --force-extra-removable

But for a persistent setup you should configure grub-efi-amd64 with

# dpkg-reconfigure grub-efi-amd64

and choose to install in the removable device path when prompted.

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#33215

On 14/09/2021 21.44, Robert Latest wrote:
> Hi all,
> 
> I have this company Windows laptop that I use privately by booting from a USB3
> SSD with a Debian installation. This used to work for years until it didn't any
> more a few days ago. Anyway, I ended up re-installing the complete Debian onto
> the same SSD again. However, I cannot figure out for the life of me how to make
> the thing bootable. The SDD usually shows up as /dev/sdc and has three
> partitions: /dev/sdc1 doesn't matter, /dev/sdc2 always was mounted under /boot,
> and /dev/sdc3 is the root device.

You probably just needed to select in the "BIOS" (actually the UEFI) to
boot from the external disk. There is usually a key that triggers that
menu. On some laptops, it is not a key on the keyboard.


> 
> 
> In order to get the thing running I boot from the Debian install USB stick,
> mount /dev/sdc3 under /mnt, do the mount --bind thing for /proc, /sys, /dev,
> and chroot into /mnt.
> 
> /dev/sdc2 is EFI type "ef", and formatted as FAT and mounted at /boot (in the
> chrooted environment). I also made a /boot/grub/efi directory.

No, it has to be mounted under boot, that is, at /boot/efi, which can
not be a directory, but a mount.

Of course, disk must be GPT.

All this should have been done automatically by the installer.


-- 
Cheers,
       Carlos E.R.

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#33216

Le 15/09/2021 à 13:59, Carlos E. R. a écrit :
> 
> Of course, disk must be GPT.

GPT is not mandatory for EFI boot (and conversely). Otherwise why does 
an "EFI system partition" type exist in DOS/MBR ?

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#33217

On 15/09/2021 14.54, Pascal Hambourg wrote:
> Le 15/09/2021 à 13:59, Carlos E. R. a écrit :
>>
>> Of course, disk must be GPT.
> 
> GPT is not mandatory for EFI boot (and conversely). Otherwise why does
> an "EFI system partition" type exist in DOS/MBR ?

If that is so, it will depend on the particular implementation in your
computer firmware. I'm not going to try. AFAIK, YaST (openSUSE
installer) refuses to do it.

-- 
Cheers,
       Carlos E.R.

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#33218

Carlos E. R. wrote:
> On 15/09/2021 14.54, Pascal Hambourg wrote:
>> Le 15/09/2021 à 13:59, Carlos E. R. a écrit :
>>>
>>> Of course, disk must be GPT.
>>
>> GPT is not mandatory for EFI boot (and conversely). Otherwise why does
>> an "EFI system partition" type exist in DOS/MBR ?
> 
> If that is so, it will depend on the particular implementation in your
> computer firmware. I'm not going to try. AFAIK, YaST (openSUSE
> installer) refuses to do it.
> 
EFI system partition - ArchWiki
https://wiki.archlinux.org/title/EFI_system_partition

"Note: It is recommended to use GPT since some firmwares might not 
support UEFI/MBR booting due to it not being supported by Windows Setup. 
See also Partitioning#Choosing between GPT and MBR for the advantages of 
GPT in general."

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#33219

Carlos E. R. <robin_listas@es.invalid> wrote:
> On 15/09/2021 14.54, Pascal Hambourg wrote:
>> Le 15/09/2021 ? 13:59, Carlos E. R. a ?crit :
>>>
>>> Of course, disk must be GPT.
>> 
>> GPT is not mandatory for EFI boot (and conversely). Otherwise why does
>> an "EFI system partition" type exist in DOS/MBR ?
> 
> If that is so, it will depend on the particular implementation in your
> computer firmware. I'm not going to try. AFAIK, YaST (openSUSE
> installer) refuses to do it.

I've got a PC which only boots via EFI and it's boot disk is DOS
partitioned, using the EFI ID for the boot partition. Works fine.

Drives (eg. USB) can be partitioned as both GPT and DOS (if you
ignore various warnings), as well as with both EFI and MBR booting
set up, so that they will boot anywhere. I've done it, but it's a
bit of a process.

-- 
__          __
#_ < |\| |< _#

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