Non-bootable media when using Kubuntu images

[pedgarcia]

Hi all,

Using the latest release, I followed the instructions to use the iso.sh script to build the ISO and use "dd" (also BelenaEtcher) to flash the USB drive.

belenaEtcher warns that the ISO doesn't contain the boot loader, and I can confirm that since the macbook I am installing it doesn't see the USB stick image (I've already removed the security and installed other linux distros there in the past).

I've tried both Kubuntu versions.

Am I missing something ?

Thanks

[AdityaGarg8]

Can you try this:

1. Power off the Mac
2. Plug in the USB stick
3. Power on and then press and hold option at boot.

[pedgarcia]

Yes, I did that (tried again now) and it doesn't see the USB stick.

FYI, I just tried the same process using the Ubuntu 25.10 images using the iso.sh script to create the ISO. With Ubuntu, belenaEtcher doesn't complain about the lack of boot loader (boot sector?). Then I tried again booting the macbook now using Ubuntu instead of Kubuntu and it worked fine - I can see the usb stick during boot and I was able to launch the live Ubuntu with no issues.

So, it seems restricted to the Kubuntu images in the release.

Let me know if there is something else I can do to debug it.

Thanks

[AdityaGarg8]

Alright, lemme see what's wrong. Is it with both 24.04 and 25.10?

[pedgarcia]

Yes, I see the same for both 24 and 25 versions.

[pedgarcia]

@AdityaGarg8 I just realized there is a new release since I tried! If you want to hold on , I will try again downloading 6.17.9.
I was trying with 6.17.8!

I will report back in one hour or so.

[pedgarcia]

Ok, I see the same issue in 6.17.9.

[AdityaGarg8]

Ok, I see the same issue in 6.17.9.

Just click continue

[pedgarcia]

I sorry, I meant to finish. I do click Continue. The USB stick is flashed but when I try to boot in the target machine, it doesn't show the USB stick as a bootable device. If I use the Ubuntu version, that message doesn't show up and I can boot. Same as before.

[AdityaGarg8]

I am unable to reproduce the issue :(

[pedgarcia]

Hey @AdityaGarg8, let me try a different Macbook and also a different USB stick.

Thanks for now.

[AdityaGarg8]

Btw @pedgarcia I used BalenaEtcher on Windows, since for some reason the Mac version was unable to flash the ISO at all for me. Maybe you can try the Windows version.

[lui75]

I am experiencing the same problem, Balena Etcher says that kubuntu_25_10 iso is not a bootable image. If I continue and flah teh iso the result is a not bootable image, not seen by the system.

[AdityaGarg8]

Are you able to use the official ISO?