Re: [gentoo-user] grub error I've never seen in many installs

[Arve Barsnes]

On 10 July 2017 at 22:06, Harry Putnam  wrote:

>  grub-install /dev/sda Installing for i386-pc platform.
> grub-install: error: cannot find a GRUB drive for /dev/sda1.  Check
> your device.map.
>
> Where might I find `device.map'... it isn't part of grub2.  At least
> grep doesn't find it with `qlist grub'
>

As far as I understand it, grub2 will dynamically create the device.map
when it needs it, so it doesn't actually exist as a file. On my grub legacy
system it is installed as /boot/grub/device.map, with the only contents
being "(hd0)   /dev/sda".

How you would feed grub this information *before* it is installed I'm not
sure, but maybe look into the USE=device-mapper flag, maybe it installs the
grub-mkdevicemap executable.

Arve

[gentoo-user] grub error I've never seen in many installs

[Harry Putnam]

Installing from install-amd64-minimal-20170706.iso into vbox vm

I've done this many times and never saw this grub error:

Attempting to run grub-install /dev/sda  I get:

 grub-install /dev/sda Installing for i386-pc platform.
grub-install: error: cannot find a GRUB drive for /dev/sda1.  Check
your device.map.

When I started googling I find hits all of which are involved with efi
drives.

I don't really even know for sure what an `efi' drive is and certainly
never had any dealings with it when installing gentoo in a vbox vm.

(Even after googling efi ... still didn't really understand what it
is. Other than what it stands for.  wikipaedia talks about a fat file
system being involved... .. all news to me)

I found something even more curious... I tried unmounting boot
(dev/sda1) and recreating the ext2 file system.

I left the computer for a bit, and when I came back I forgot I had
not remounted boot, and ran `grub-install /dev/sda' again with /dev/sda1
unmounted.

It ran with no errors and created a grub directory on / (/dev/sda4)

I don't understand why grub is looking for a GRUB drive on /dev/sda1
when I asked it to install on /dev/sda

The error tells me to check `device.map'.  But gives no clue where it
might be found.

Where might I find `device.map'... it isn't part of grub2.  At least
grep doesn't find it with `qlist grub'

Near as I can tell I've done things ... so far in the same way I have
before several times... probably within 4 to 6 mnths.  So I may be
forgetting something important... but I know I have never run across
this error before.

And I have followed the handbook at least mostly.