[Bug 1955611] Re: Unable to boot Live USB on Mac

[Chris Guiver]

Thank you for taking the time to report this issue and helping to make
Ubuntu better.

This package failure looks like it was caused by bad ISO download,
corrupted install media, or device failure, assuming /dev/sdb is your
installation media; the error "/dev/sdb: No medium found" is an ability
to recognize the media as valid. The question to attempt to download is
the solution offered in that circumstance.

Possibly useful : https://tutorials.ubuntu.com/tutorial/tutorial-how-to-
verify-ubuntu#0   though it sounds like that was not your issue (having
performed checks), but the writing of the ISO was not done correctly
(possibly with older software that couldn't cope with 20.04.3 media).

For Support, this bug report can be converted into a question, or you
can ask a question on https://answers.launchpad.net/ubuntu. You can also
find help with your problem in the support forum of your local Ubuntu
community http://loco.ubuntu.com/ or asking at https://askubuntu.com or
https://ubuntuforums.org, or for more support options please look at
https://discourse.ubuntu.com/t/community-support/709


** Package changed: ubuntu => syslinux (Ubuntu)

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https://bugs.launchpad.net/bugs/1955611

Title:
  Unable to boot Live USB on Mac

Status in syslinux package in Ubuntu:
  New

Bug description:
  Live USB boot reaches grub but fails some time after and fails to
  completely boot on Macbook Pro 11,3 with Ubuntu 20.04.3

  After selecting 'Ubuntu' or 'Ubuntu with safe graphics' the splash
  screen shows, and after a while the screen is filled with lines of
  `/init: line 49: can't open /dev/sdb: No medium found` with one line
  at the bottom of `Unable to find a medium container a live file
  system. Attempt interactive netboot from a URL?`

  Booting with debug option from grub does not give keyboard access. I
  have attached a photograph of the output at boot time to this ticket
  as extracting logs from the system does not seem possible.

  Full hardware specs of the exact model can be found here:
  https://everymac.com/systems/apple/macbook_pro/specs/macbook-pro-
  core-i7-2.5-15-dual-graphics-mid-2014-retina-display-specs.html

  The iso file used is ubuntu-20.04.3-desktop-amd64.iso

  The SHA256 of the downloaded iso file and MD5 sum of all files on the USB using the included md5um.txt have been confirmed OK.
  All USB ports on the machine, and multiple USB devices have been tested.
  The Live USB install boots to Ubuntu desktop when run from within a virtual machine under VMWare Player 16.

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