To check whether the download has included the efi boot files one could mount the iso, as root, and navigate to the EFI directory and inspect the contents thus:
Code:
root@min:# mount /home/tom/Downloads/lubuntu-24.04-desktop-amd64.iso /mnt
mount: /mnt: WARNING: source write-protected, mounted read-only.
Then as user:
Code:
[tom@min ~]$ cd /mnt
[tom@min /mnt]$ ls
boot casper EFI md5sum.txt preseed
boot.catalog dists install pool ubuntu
[tom@min /mnt]$ cd EFI
[tom@min /mnt/EFI]$ ls
boot
[tom@min /mnt/EFI]$ cd boot/
[tom@min /mnt/EFI/boot]$ ls
bootx64.efi grubx64.efi mmx64.efi
To unmount, leave the /mnt directory and run:
The three files in the EFI/boot directory are fine and this iso can boot from a usb after being written to the usb.
If the downloaded iso looks to have the booting files, but Balena Etcher says it's not bootable, then a straight forward way of checking is to the write the iso file to a usb with another program like dd or cp using root, e.g.
Code:
# cp lubuntu-24.04-desktop-amd64.iso /dev/sdX
# sync
# dd if=lubuntu-24.04-desktop-amd64.iso of=/dev/sdX
where /dev/sdX is the usb device. The command: lsblk will usually show it.
These commands do a bit by bit copy which doesn't add padding such as zeros which sometimes gets added by some other programs. The bit by bit command maintains the physical integrity of the original iso.
When using programs like ventoy and balena etcher, one is using extra layers of software over the fundamental processes involved, so when a problem like the one described occurs, it can be difficult to know which software to look at, or which is responsible, if any. Shearing things back to more basic programs will eliminate the overlaying software and can help with resolving the issues.
In this case of lubuntu, the download was made with the robust and reliable program wget, thus:
Code:
[tom@min ~/Downloads/work]$ wget https://cdimage.ubuntu.com/lubuntu/releases/24.04/release/lubuntu-24.04-desktop-amd64.iso
--2024-07-22 11:40:17-- https://cdimage.ubuntu.com/lubuntu/releases/24.04/release/lubuntu-24.04-desktop-amd64.iso
Resolving cdimage.ubuntu.com (cdimage.ubuntu.com)... 2001:67c:1562::28, 2001:67c:1562::25, 2620:2d:4000:1::17, ...
Connecting to cdimage.ubuntu.com (cdimage.ubuntu.com)|2001:67c:1562::28|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3296555008 (3.1G) [application/x-iso9660-image]
Saving to: ‘lubuntu-24.04-desktop-amd64.iso’
lubuntu-24.04-desktop-amd64.iso 100%[====================================================================================================>] 3.07G 9.62MB/s in 5m 17s
2024-07-22 11:45:35 (9.91 MB/s) - ‘lubuntu-24.04-desktop-amd64.iso’ saved [3296555008/3296555008]
It's worth mentioning that there are options to the programs that have been used above which the user can use to refine their operations, but the basics described here all have worked reliably here for decades.
