[Bug 1433229] [NEW] [live-usb-persistent] Booting fails after kernel update in 12.04.2, 13.04, and 14.04.2

[linuxball]

Public bug reported:

When a 64-bit Lubuntu 14.04.2 persistent Live system on an USB flash
drive (LiveUsbPendrivePersistent) is upgraded so that a new kernel is
installed then the next (re)boot will fail. The user is dropped to the
busybox shell prompt of the initial RAM file system:

  BusyBox 1.21.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell (ash)
  Enter 'help' for a list of built-in commands

  (initramfs) Unable to find a medium containing a live file system

CAUSE:
I found out that newer 64-bit Ubuntu live file systems use casper/vmlinuz.efi for booting (instead of casper/vmlinuz). However, casper copies the updated kernel image still as casper/vmlinuz. Thus the next system (re)start will boot the old casper/vmlinuz.efi along with the casper/initrd.lz for the newer updated kernel. This results in the above reported boot failure.

RELATED BUGS/QUESTIONS:
https://bugs.launchpad.net/uck/+bug/1201911
https://answers.launchpad.net/uck/+question/260822

HOW TO REPRODUCE:
* Download iso image http://cdimage.ubuntu.com/lubuntu/releases/14.04.2/release/lubuntu-14.04.2-desktop-amd64.iso
* Install it on USB flash drive using Startup Disk Creator, choose documents and settings will be
   "Stored in reserved extra space" with e.g. 4GB
* Boot from live system
* Open a terminal and execute "sudo apt update && sudo apt upgrade"
* Reboot after upgrading has finished 

WORK AROUND:
* Everytime after a new kernel has been installed execute "sudo mv /cdrom/casper/vmlinuz /cdrom/casper/vmlinuz.efi"

FIX:
see attached "casper vmlinuz.efi fix"

** Affects: casper (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: trusty

** Attachment added: "casper vmlinuz.efi fix"
   https://bugs.launchpad.net/bugs/1433229/+attachment/4348069/+files/casper-update-initramfs.patch

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https://bugs.launchpad.net/bugs/1433229

Title:
  [live-usb-persistent] Booting fails after kernel update in 12.04.2,
  13.04, and 14.04.2

Status in casper package in Ubuntu:
  New

Bug description:
  When a 64-bit Lubuntu 14.04.2 persistent Live system on an USB flash
  drive (LiveUsbPendrivePersistent) is upgraded so that a new kernel is
  installed then the next (re)boot will fail. The user is dropped to the
  busybox shell prompt of the initial RAM file system:

    BusyBox 1.21.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell (ash)
    Enter 'help' for a list of built-in commands

    (initramfs) Unable to find a medium containing a live file system

  CAUSE:
  I found out that newer 64-bit Ubuntu live file systems use casper/vmlinuz.efi for booting (instead of casper/vmlinuz). However, casper copies the updated kernel image still as casper/vmlinuz. Thus the next system (re)start will boot the old casper/vmlinuz.efi along with the casper/initrd.lz for the newer updated kernel. This results in the above reported boot failure.

  RELATED BUGS/QUESTIONS:
  https://bugs.launchpad.net/uck/+bug/1201911
  https://answers.launchpad.net/uck/+question/260822

  HOW TO REPRODUCE:
  * Download iso image http://cdimage.ubuntu.com/lubuntu/releases/14.04.2/release/lubuntu-14.04.2-desktop-amd64.iso
  * Install it on USB flash drive using Startup Disk Creator, choose documents and settings will be
     "Stored in reserved extra space" with e.g. 4GB
  * Boot from live system
  * Open a terminal and execute "sudo apt update && sudo apt upgrade"
  * Reboot after upgrading has finished 

  WORK AROUND:
  * Everytime after a new kernel has been installed execute "sudo mv /cdrom/casper/vmlinuz /cdrom/casper/vmlinuz.efi"

  FIX:
  see attached "casper vmlinuz.efi fix"

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