Recent (Nov 2020) ISO copied to USB Drive cannot load

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

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

Bug reporting is mostly about finding & fixing problems thus preventing future users from hitting the same bug.

Ubuntu 20.10 was released in 2020-October (thus it's 20.10) and there have been no Ubuntu releases in November unless you include development/test releases (20.04.2, hirsute (21.04) etc)

There is no evidence of validate of ISO (esp. given the date stamp on the file you mention is wrong), etc. so I'd suggest it's a support issue.

I believe would be more appropriate, eg. 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

I've accordingly marked this incomplete, if you believe I'm in error, or you've verified your ISO & believe it is an actual bug in the software/ISO, you can leave another message on this report and change the status back to "New". Please also provide specific details as to ISO, the sha256sums etc & details of how you verified they were valid.

FYI: Yes a number of changes were made during the groovy cycle in the way systems are booted, and they were gradually fixed as detected, eg. https://bugs.launchpad.net/bugs/1883040 https://bugs.launchpad.net/bugs/1886148 & others. You however haven't provided proof that normal validation of ISOs has been performed, checksums of ISOs matching what they should be etc.

This looks like an error in the tool you've used to write the image to the USB disk, not a bug in the image.

As far as I understand, Startup Disk Creator is not software that's part of Ubuntu; so closing this bug rather than reassigning.

@vorlon "Startup Disk Creator" is the name in the desktop.file of the usb-creator that we do ship in the archive, and I think we created...

However, I do wish people would use "GNOME Disks" to restore .iso on usb stick =/

I forgot to mention the following :-

GRUB states "Error can't find command grub_platform

The USB stick loads perfectly on an UEFI laptop
The USB stick loads with "Safe Graphics" on an Intel platform

I have used dd if=ubuntu-20.10-desktop-amd64.iso of=dev/sdc with a direct download

There are others who are experiencing this problem.

The boot used by latest distros HAS CHANGED............

Adversely affecting AMD BIOS based motherboards

I also missed the sha256sum of my directdownload was
04c343811e58cf35d9b10397cc7324f486f8b32c5996111752378d4981efcf87

which matches with
04c343811e58cf35d9b10397cc7324f486f8b32c5996111752378d4981efcf87 *ubuntustudio-20.10-dvd-amd64.iso

Wht are all New distro ISO files (Oct 2020 on) now created with GUID Partition Tables. ??????

These work fine when used to create USB Boot Sticks for new Secure Boot systems,

 HOWEVER these ISOs FAIL to load on many BIOS machines. ( GRUB ERROR - Command GRUB_PLATFORM missing )

SOLUTION
=========
mount the GUID based iso on /dev/loopX using Mount Disk Image.
sudo gdisk /dev/loopX
Recovery option (r) convert to MBR (g)
then use Startup Disk or Gnome Disk or dd to create an MBR based USB Stick

Tested with ubuntustudio-20.10-dvd-amd64.iso and xubuntu-20.10-dvd-amd64.iso

I had the same error with today's ubuntu-20.10-desktop-amd64.iso image on a Shuttle SG45H7 system with an Intel Core2 Duo E4400:

  GRUB Error: can't find command "grub_platform"

Which then leads to a blinking cursor black screen after selecting any GRUB entry.

An alternative solution that works is to flash the ISO to the USB drive with Startup Disk Creator then convert it to MBR.

# sudo fdisk -l /dev/sdb
GPT PMBR size mismatch (5746099 != 123404287) will be corrected by write.
The backup GPT table is not on the end of the device.
Disk /dev/sdb: 58,84 GiB, 63182995456 bytes, 123404288 sectors
Disk model: Transcend 64GB
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 7EE1FFAC-4072-46B8-885E-A7EA3F9C70CF

Device Start End Sectors Size Type
/dev/sdb1 64 5735483 5735420 2,7G Microsoft basic data
/dev/sdb2 5735484 5745435 9952 4,9M EFI System
/dev/sdb3 5745436 5746035 600 300K Microsoft basic data

# sudo gdisk /dev/sdb
GPT fdisk (gdisk) version 1.0.5

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): r

Recovery/transformation command (? for help): ?
b use backup GPT header (rebuilding main)
c load backup partition table from disk (rebuilding main)
d use main GPT header (rebuilding backup)
e load main partition table from disk (rebuilding backup)
f load MBR and build fresh GPT from it
g convert GPT into MBR and exit
h make hybrid MBR
i show detailed information on a partition
l load partition data from a backup file
m return to main menu
o print protective MBR data
p print the partition table
q quit without saving changes
t transform BSD disklabel partition
v verify disk
w write table to disk and exit
x extra functionality (experts only)
? print this menu

Recovery/transformation command (? for help): g

MBR command (? for help): ?
a toggle the active/boot flag
c recompute all CHS values
l set partition as logical
o omit partition
p print the MBR partition table
q quit without saving changes
r set partition as primary
s sort MBR partitions
t change partition type code
w write the MBR partition table to disk and exit

MBR command (? for help): w

Converted 3 partitions. Finalize and exit? (Y/N): y
GPT data structures destroyed! You may now partition the disk using fdisk or
other utilities.

# sudo fdisk -l /dev/sdb
Disk /dev/sdb: 58,84 GiB, 63182995456 bytes, 123404288 sectors
Disk model: Transcend 64GB
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device Boot Start End Sectors Size Id Type
/dev/sdb1 64 5735483 5735420 2,7G 7 HPFS/NTFS/exFAT
/dev/sdb2 5735484 5745435 9952 4,9M ef EFI (FAT-12/16/32)
/dev/sdb3 5745436 5746035 ...

Same happens to me on an Ubuntu 21.04 beta iso. It boots perfectly on an EFI laptop but fails on my PC with BIOS. I tried creating the bootable usb drive with startup-disk-creator and get the same results too with gnome-disks using the restore disk image.
And it is not the first time I see that. I tried with several daily builds of Hirsute Hippo and always fails.
I get the same error message too: Error can't find grub_platform.
I think that is clearly a bug. But I don't know against which package should be filled.

Besides that, I don't known if it is better to continue with this bug or create a new one.

If you look at the freshly written image with Gnome disks , 1st ubuntu partition , click the cog wheel and choose edit partition you'll notice that the build team have not enabled the Legacy BIOS bootable option?

If you enable it and click change the drive will now boot , there is still a really long 20 second pause with a black screen and blinking cursor but it eventually swaps over to the Ubuntu boot logo and starts.

Ubuntu version: 20.10 Groovy Gorilla.
PC motherboard: Gigabyte 880GM-USB3 (rev3.1).
The problem: Using Ubuntu's startup disk creator, I created an image of Groovy Gorilla's ISO onto a pen drive (formatted with NTFS). I booted from the pen drive and am shown an error: "cannot find grub_platform". Then I'm presented with a blank screen with a blinking cursor at the top left corner of the screen. It remains stuck at that.
Someone else who experienced this: https://askubuntu.com/questions/1288476/can-not-install-from-usb-with-error-cannot-find-grub-platform/1335403.

Solution: As pdecat mentioned, converting GPT to MBR helps.

Why this needs fixing: Not everyone uses a modern PC with UEFI support. Just as in this bug (https://bugs.launchpad.net/ubuntu/+source/shim/+bug/1867092/comments/28), all sub-versions of Ubuntu 20 and above, need to be patched to have some kind of legacy support. Not all users would have sufficient tech knowledge to search and find this solution.

This affected me. I downloaded kubuntu-22.10-desktop-amd64.iso on Jan 20, 2023. Initially, I used dd to write the .iso to a 32GB USB stick (PNY), and again using balena Etcher. In both instances, I booted the resulting Live USB on my "pre-2015" HP Pavilion g7-1070us Notebook PC. I was presented with the GRUB menu, but selecting *Try or Install Kubuntu I was briefly shown "Error can't find grub_platform" and then the blinking cursor in the upper left corner. A power off is required at that point. Based on the error message, I Googled and found this report. The fix; converting the GPT of the created LiveUSB to MBR works. But this really does need to be addressed and fixed. Not everyone has modern, UEFI capable, PCs. I don't. Lessor informed users, or those without the trouble shooting skills, will be turned off by the experience.