can't boot from external media

[rybnik]

I have a ThinkPad L540. I used to be able to boot it from both live DVDs and live USB flash drives, but now I can't boot from external media at all. The computer only lets me boot from the hard drive.

Thanks in advance.

[Snowhog]

Access the BIOS and check your Boot options and device order.

[rybnik]

Yes, that's occurred to me. Putting optical drive (or USB port) at the top of the boot order doesn't help anything. Nor does one-time boot override. (F12 on a lenovo)

The problem is deeper than that.

[Snowhog]

Once booted and logged in, can you access a DVD and/or USB when inserted?

[Qqmike]

Thought ...

The ThinkPad L540 is fairly new, right (later than 2011 or so)? If so, it probably boots by UEFI (not by the older BIOS). Make sure you disable CSM in the UEFI setup menus. Make sure your external boot media is UEFI (Kubuntu must be 64-bit, not 32-bit; similarly, check other media for their UEFI download options). When you re-boot with the external media (e.g., DVD) inserted, enter your UEFI ("BIOS") setup menu, find the boot menus, find that DVD in the list of boot options, make sure the DVD listed says something like UEFI/EFI DVD [Samsung, whatever etc etc etc], and select THAT option to boot (i.e., don't try to boot the "usual" non-UEFI boot listing of the DVD).

[rybnik]

Once booted and logged in, can you access a DVD and/or USB when inserted?

Absolutely.

The ThinkPad L540 is fairly new, right (later than 2011 or so)?

I bought it in Dec. 2013.

Make sure you disable CSM in the UEFI setup menus. Make sure your external boot media is UEFI (Kubuntu must be 64-bit, not 32-bit; similarly, check other media for their UEFI download options). When you re-boot with the external media (e.g., DVD) inserted, enter your UEFI ("BIOS") setup menu, find the boot menus, find that DVD in the list of boot options, make sure the DVD listed says something like UEFI/EFI DVD [Samsung, whatever etc etc etc], and select THAT option to boot (i.e., don't try to boot the "usual" non-UEFI boot listing of the DVD).

Yes, tried all that. The problem is deeper.

[rybnik]

Could updating the firmware help? I've never done that, and I'm a bit hesitant to try because I read it's dangerous.

[Qqmike]

Could updating the firmware help? I've never done that, and I'm a bit hesitant to try because I read it's dangerous.

I don't know.

Personally, I am very conservative about updating firmware (i.e., I resist doing it). But, you never know. You can check the available firmware updates for your machine and see if any make sense for the issue(s) you have. In theory, it should not hurt ... ASUS, to mention another maker, is real good about flashing "BIOS." You need to do it with USB backup or backup file or some such thing.

You would think that you do not need any NEW machine capabilities because your (old firmware) machine did boot from media that is "older," like 14.04.

Hate to suggest this, because it sounds like you probably already did it: google the problem?
Like
can't boot ThinkPad L540 from DVD (or you could try other searches, like external media, etc.)
and get
https://www.google.com/search?client...+E540+from+DVD

There may be some hints or tips to be found.

Is your existing external media (DVD, USB) still good? not damaged or anything?

[rybnik]

Hate to suggest this, because it sounds like you probably already did it: google the problem?

Yes. The issue is that when I google this, the results are threads that pertain to people who've never installed an OS before and want to, on a machine without issues, learn how to boot from external media.

Is your existing external media (DVD, USB) still good? not damaged or anything?

Yep.

The problem is less severe than I anticipated. I still can't boot from USB, but I realized today that I can now boot from certain DVDs but not others. I was able to boot from DVDs of openSUSE 13.1 and PC-BSD 10. Not sure what's special about those two...

At any rate, 14.04 is supported until April 2019. So I'm guaranteed at least three more years of kubuntu use on this computer. Then I... switch to PC-BSD? lol

[Frank616]

FWIW, I have one machine that will not boot a disc burned on another one. There is just enough difference between the tracks on the two drives that they don't work well.

A shot in the dark.

Frank.

[Shabakthanai]

I had this problem recently, Dibl and Qqmike have the solution.

I did not notice your Operating System, but there seems to be a known bug in the Kubuntu 15 version. Apparently in doesn't affect everyone, but those who have the bug report a similar problem.

I had other problems with my computer too, so I am slightly apprehensive giving advice, but I thought knowing that K15 has a known bug on the matter would be useful information.

In my situation, when I started my computer the grub rescue> prompt appeared. If you are getting this prompt and trying to install another system, type in the word 'live' at the prompt. If it opens your system to the USB ISO, you can install your chosen version. Next time you restart, you may have to open the BIOS and select the USB entry for a boot selection.

Then the next time you restart your computer the problem should be resolved and the USB port functioning.

There are many whose advice is solid, Snowhog, Vinny, Qqmike and Dibl are a safe guru to follow, also many others, RodJ too, there are several, but those are pretty sure as advisors and give stable advice.