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Disclaimer: I'm a newb and I need step by step guide. Thanks!

I want to first install grub without OS, since it will boot from ISO file off the local network storage. I'm booted into a liveCD (I can't install it since I need a volatile system) I'm already stuck at first stage. I tried grub-install /dev/sda and I get error saying grub-install: error: cannot open directory '/boot/grub/i386-pc': No such file or directory.

So I created and copied all files it grub-install needed and now it says grub-install: error: failed to get canonical path of 'aufs'.

I searched web and figure most answers requires me to use chroot while I have a installed system (can be broken though) I don't have Ubuntu installed to any drive and my goal is to install grub from liveCD to empty drive.

I want to start with an empty boot loader.

How do I do this?

Thanks again in advance.

2 Answers 2

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You should not need the full Linux file structure if just booting an ISO. I have installed grub to flash drive with various formats and booted ISO on that same flash drive. Not sure exact grub boot stanza required for network boot.

I had an old USB2 flash drive which I reformated. I first make it gpt, as I prefer that over the now 40 year old MBR partitioning. You can use gparted which I normally do. Select gpt under device, advanced over msdos(MBR) default partitioning before starting. or use parted or gdisk. Note: This totally erases drive. The sdX, is your flash drive.

sudo parted /dev/sdX mklabel gpt

I then used gparted to create on large FAT32 partition. I had to reboot for it to be seen correctly & file browser does not auto mount ESP partitions, so used Disks or manually mount.

Model: Kingston DataTraveler 2.0 (scsi)
Disk /dev/sdc: 1998MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name  Flags
 1      1049kB  1998MB  1996MB  fat32        esp2  msftdata

I then mounted it with disks and then it was in /media/fred:

/dev/sdc1 on /media/fred/FC87-F75C type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)

Then installed grub. My drive was seen as sdc. Was a bit slow as old USB2 flash drive.

sudo grub-install --root-directory=/media/fred/FC87-F75C /dev/sdc

It created structure and the normal /EFI/ubuntu/grub.cfg that is a 3 line configfile to full grub in /boot/grub/grub.cfg. But did not create any /boot/grub/grub.cfg boot file. I normally manually created one to boot local ISO using these references & my older notes. You will have to create a grub.cfg but with path & mount? to network.

ISO boot & link to examples

https://help.ubuntu.com/community/Grub2/ISOBoot

more examples

https://help.ubuntu.com/community/Grub2/ISOBoot/Examples

Network grub info I found using google. nfs will not work, but has example for net boot.

Set up nfsroot for GRUB PXE

How to boot linux kernel from network through GRUB2 console?

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  • sudo parted /dev/sdX mklabel gpt then formatted my device to fat and mounted it sudo grub-install --root-directory=/media/ubuntu/XXXX-XXXX /dev/sdX This worked really well. Thanks!
    – newbie
    Commented Jan 26, 2021 at 16:14
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You don't need an installed system. First you have to mount the disk, from now we will use as example sda. As a mountpoint example /media/usr/DISK

In a terminal, use this code:

dirs=(etc bin usr proc sys lib lib64 dev sbin)

for dir in ${dirs[@]}; do
  mkdir /media/usr/DISK/$dir
  sudo mount --bind /$dir /media/usr/DISK/$dir
done

sudo chroot /media/usr/DISK/ grub-install --target=i386-pc --boot-directory=/ /dev/sda

for dir in ${dirs[@]}; do
  sudo umount /media/usr/DISK/$dir
  rm -r /media/usr/DISK/$dir
done

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