first to boot into Ubuntu from iso.
1.Locate the Ubuntu partition and the folder containing the Grub modules.
The Grub folder containing the modules must be located so the correct modules can be loaded. This folder would have been created during the initial installation of Ubuntu and should be located in the Ubuntu partition. This folder would normally be located at either (hdX,Y)/boot/grub or (hdX,Y)/usr/lib/grub/i386-pc
Find your existing Ubuntu partition and the module folder.
ls # List the known drives (hdX) and partitions (hdX,Y)
ls (hdX,Y)/ # List the contents of the partition's root
ls (hdX,Y)/boot/grub # Normal location of the Grub 2 modules.
ls (hdX,Y)/usr/lib/grub/i386-pc # Alternate location of the Grub 2 modules.
ls - should return all known drives (hdX) and partitions (hdX,Y)
ls (hdX,Y)/ - should show the contents of the root directory of the
- If you get an "error: unknown filesystem" this is not your Ubuntu
- If this is the Ubuntu partition, you will see the Ubuntu
folders, including lost+found/, home/, boot/ and vmlinuz and
initrd.img. Use this address as the first part of the next
ls (hdX,Y)/boot/grub - should display several dozen *.mod files. This is the folder you are looking for.
- If you don't find the modules, try the alternate location: ls (hdX,Y)/usr/lib/grub/i386-pc
2.Load the modules.
set prefix=(hdX,Y)/<path to modules>
- This command must correctly point to the folder containing the Grub modules. The address should be the one in the previous section which displayed the modules.
insmod fat # If ISO is located on fat16 or fat32 formatted partition.
insmod ntfs # If ISO is located on an NTFS formatted partition.
insmod nftscomp # If NTFS compression is used on the partition. Load if you aren't sure.
A "file not found" error means that the path in the prefix is incorrect or the specific module does not exist. The prefix setting may be reviewed with the set command. Rerun the "set prefix=" command with the proper path.
3.Locate the Ubuntu ISO file.
- Using the combinations of ls commands, locate the Ubuntu ISO image.
4.Create the loopback device.
loopback loop (hdX,Y)/<path to ISO>/<ISO-name.iso>
5.Load the Linux kernel and initrd image.
linux /casper/vmlinuz boot=casper iso-scan/filename=/<ISO-name.iso> noprompt noeject
further info here
Now do this after booting ::
here is post with same problem and is solved as below,
sudo mount /dev/sdaX /mnt
sdaX is your boot partition. you can get list with
sudo blkid like this,
/dev/sda1: LABEL="Windows XP" UUID="96A4390DA438F0FB" TYPE="ntfs"
/dev/sda3: LABEL="Ubuntu 11.04" UUID="b61fcae3-7744-45b4-95b9-7528d50a3652" TYPE="ext4"
/dev/sda5: LABEL="Se7en" UUID="A2DC9D71DC9D4109" TYPE="ntfs"
/dev/sda6: LABEL="Development" UUID="DEB455A1B4557CC9" TYPE="ntfs"
/dev/sda7: LABEL="EXTRA" UUID="D8A04109A040F014" TYPE="ntfs"
/dev/sda8: LABEL="SONG" UUID="46080FCD080FBAC7" TYPE="ntfs"
/dev/sda9: LABEL="BACKUPS" UUID="766E-BC99" TYPE="vfat"
sdaX must be linux partition.
sudo grub-install --boot-directory=/mnt/boot /dev/sda