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this is a Ubuntu-only machine. No Windows, no dual boot. It's a Dell, with UEFI boot protocol (Inspiron 5559).

I wrecked my 14.04 installation by trying to upgrade the kernel (following instructions at https://websetnet.com/install-linux-kernel-45-rc-3-ubuntu-1504-ubuntu-1404/). The advice was followed because I have no sound and they said I needed a newer kernel.

The command to remove the newer kernel failed.

Anyway, I now have a machine which sometimes refuses to boot, and sometimes can be persuaded to boot to the older kernel in recovery mode. It's effectively useless.

More than anything, I would like to remove the entire installation and reinstall from scratch, but I can't. The boot sequence won't let me boot from the Ubuntu live CD, and I don't know how to get the CD to run.

I've backed up my /home directories, by the way.

Grateful for any help.

Cheers John

John M.
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  • Fortunately for you, you do not to change the boot order, or deal with DVDs and USB sticks in your situation. There is, indeed, the possibility to boot an iso directly, as described in the official guide https://help.ubuntu.com/community/Grub2/ISOBoot – dadexix86 Feb 27 '16 at 13:16
  • Ubuntu should be a DVD unless perhaps Lubuntu. And better, easier to use flash drive. From UEFI one time boot key you should get two boot options for DVD or flash drive, one UEFI and one just name of flash drive or BIOS. You only want UEFI boot. UEFI only USB key, just extract ISO ( 7 zip or similar) to FAT32 formated flash & set boot flag. http://askubuntu.com/questions/395879/how-to-create-uefi-only-bootable-usb-live-media – oldfred Feb 27 '16 at 15:38
  • You can usually boot external media by using the computer's built-in boot manager. Unfortunately, there's NO industry standardization on how this works, or even how to access it. It's usually accessed via the Esc key, Enter key, or a function key (typically F8 or above) soon after you power on the computer. There may or may not be a prompt to hit the relevant key. The window for hitting the key is usually narrow, so the usual procedure is to power on and keep hitting the key once or twice a second until you see the boot manager menu appear. – Rod Smith Feb 27 '16 at 16:51
  • Thank you for your answers.

    I can't boot anything except the hard drive. The UEFI BIOS won't let me change the boot sequence, and it doesn't recognise the DVD drive.

    I tried the GRUB 2 option, but the /boot/grml directory is nowhere near large enough for the iso file. Not even close. I get an error when I try to copy it.

    So, can anyone tell me how to invoke the CD or USB drive (I have a USB stick with the 15.10 iso on it) for a total reinstall? I really really want to start again.

     – John M. Mar 01 '16 at 18:17

2 Answers2

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   sudo dpkg -l | grep linux-image

this will display the kernels purge the newer one by this

sudo apt-get purge linux-image-3.13.0-76-generic

update grub by this

sudo update-grub

change the version with your one

but first check if you can boot into the machine with older kernels selecting an older kernel from the advanced option in grub

Shantanu Bedajna
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couldn't use Grub 2, couldn't boot CD or flash drive, couldn't do squat.

So I deleted the files in /boot that were associated with the new (4.5-rc) kernel - in other words, everything with "4.5" in the file name.

Not very scientific or sensible, but after rebooting, the PC finally 'noticed' the flash drive and booted into Ubuntu Live. I think this happened because I'd done something unspeakable to the boot files: reason I believe this is because Ubuntu told me there was no operating system, so I must have done something to remove some crucial part of it.

So, at this point in the tale, I'd done everything I shouldn't have. Once Ubuntu booted, it all got a lot easier.

Remember, I followed instructions to update the kernel because I wanted sound. Well, Ubuntu 15.10 (on the flash drive) solved that problem, so I'm a happy bunny.

Took 3 evenings to restore everything else, but now I have a laptop where sound and the HDMI port both work, so I can stream online TV catch-up programmes.

All good, thanks to all who took the trouble to contribute.

JM

Kristopher Ives
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John M.
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