Results 1 to 2 of 2

Thread: Dual boot machine: grub fails during upgrade from 18.04 to 20.04

  1. #1
    Join Date
    Jun 2022

    Dual boot machine: grub fails during upgrade from 18.04 to 20.04

    The upgrade process successfully created the Focal Foss desktop. But after prompted to reboot, grub produced an error. (Tried a cold boot: same issue. Tried advanced reboot: same issue when top choice chosen, i.e. 5.4.0-121-generic .) Here's the error in grub:

    [    2.641286]  sd 6:0:0:0: [sdb] No Caching mode page found
    [    2.641294]  sd 6:0:0:0: [sdb] Assuming drive cache: write through
    Gave up wainting for root file system device.  Common problems:
     - Boot args (cat /proc/cmdline)
         - Check rootdelay= (did the system wait long enough?)
       - Missing modules (cat  /proc/modules; ls /dev)
    ALERT!  /dev/sda6 does not exist. Dropping to a shell!
    BusyBox v1.30.1 (Ubuntu 1:1.30.1-4ubuntu6.4) built-in shell (ash)
    Enter 'help' for a list of built-in commands
    The last word in parentheses is a command prompt.

    This is an HP Z220 dual boot windows desktop with Win 10 (upgraded from win7, which borked grub back in Nov 2020).

    I started using Ubuntu dual boots back in 2010, and am still a noob. (Maybe I should run Linux in a mini-PC.)

    What's the next step? Mess with BusyBox, whatever that is? Edit the grub file? (If so, how do I locate it and how do I edit it?) Re attempt this with a fresh install via USB? (Not a problem - I backed up all my data.) Try a recovery Linux installation in grub? Something else? I fix grub issues every few years and invariably have no memory of my previous adventure.
    Last edited by ajgreeny; June 30th, 2022 at 09:33 PM. Reason: Code tags added

  2. #2
    Join Date
    Jun 2010
    London, England
    Ubuntu Development Release

    Re: Dual boot machine: grub fails during upgrade from 18.04 to 20.04

    When you select Advanced Options for Ubuntu what Linux kernels do you see? My Ubuntu 20.04 is on Linux 5.13. I am guessing that the 5.4 kernel is left over from Ubuntu 18.04. If Grub cannot find the Linux kernel and then we get dropped to a Grub prompt. Ending up with BusyBox is another matter entirely. It indicates that the partition is corrupted.

    It is a machine. It is more stupid than we are. It will not stop us from doing stupid things.
    Ubuntu user #33,200. Linux user #530,530

Tags for this Thread


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts