Create USB stick for old non-uefi system

I am struggling a lot with the creation of a bootable usb stick for Ubuntu. I used various tools (gnome disk, unetbootin) to accomplish that but the problem is that none of the methods created a USB that could be booted on an old system with no UEFI bios (Dell XPS l502x). Basically, whenever I boot from USB I get the "Operation System not found" message. The same USB on a recent (UEFI) laptop boots up nicely.

I suspect the reason might be that I need to created an MBR partition table instead of the GPT. However none of the tools I tested offeres the option to manually select MBR or GPT. I read about Rufus, but I have no access to a Windows machine to test that. I have this problem since 20.04.

I guess I could accomplish it using dd from CLI, does anybody have any suggestion?

thanks

As already stated in comments, Ubuntu ISOs are tested and if written currently as per documentation

• https://ubuntu.com/tutorials/tutorial-create-a-usb-stick-on-ubuntu#1-overview
• https://ubuntu.com/tutorials/tutorial-create-a-usb-stick-on-macos#1-overview
• https://ubuntu.com/tutorials/tutorial-create-a-usb-stick-on-windows#1-overview

they will boot on

• legacy BIOS/csm hardware
• uEFI hardware
• Secure uEFI hardware

ISOs up to Ubuntu 20.04 LTS were pretty consistent in format, with few real changes between releases (alas with differences between architectures).

From Ubuntu 20.10 and later an effort is made to ensure all architectures of a given release boot the same way, thus small variations in ISO exist for releases newer than Ubuntu 20.04 LTS. Thus if using software to write an ISO >20.04, it needs to be updated to cope with the release you're wanting to use (as do procedures if you're reformatting the ISO yourself; older procedures only work up to 20.04 - which is the release you mention).

If you use a pure clone (can be called dd-write or dd-mode on some software) all ISOs will write however, the issue relates to programs or procedures that re-format the ISO causing it to differ to the ISO you download from ubuntu.com. Some of these re-format options can write an ISO that boots only in specific modes (such as uEFI only, or BIOS only), but it will fail to boot elsewhere.

Wrong architecture

Another reason a modern ISO may fail to boot, is user-procedural, ie. you try and boot it on hardware that's incapable of executing it. eg. trying to boot an amd64 ISO on i386 hardware may produce a

"Kernel requires an x86-64 CPU but only detected i686"

error message, alas not always (https://bugs.launchpad.net/ubuntu-cdimage/+bug/1895956)

Slow to boot - be patient

Some hardware takes awhile to boot, eg. I have hardware that takes >12 minutes to boot an ISO, which includes 9+ minutes where nothing is shown on screen (which makes users believe it's failed, when its just struggling with non-compliant BIOS firmware bugs). Some sites suggest using the aforementioned re-format options to allow a faster boot in these cases, where I'll suggest just waiting, as using the re-format options that speed it on one machine will mean it'll fail to boot on others. The issue with https://bugs.launchpad.net/ubuntu/+source/casper/+bug/1922342 may or may-not be fixed for some releases, but the answer here is just be patient (wait 15 minutes).

I use hardware as old as from 2005 in my Quality Assurance testing of Ubuntu ISOs (mainly Desktop inc. some flavors), and all releases have booted on my hardware from 2005+. I used older hardware (2002+) for releases up to late-2021 that was i386 only, but newer ISOs aren't created for that architecture anymore.

As far as I know the only Ubuntu like system that has up to date installs for 32 bit is Emmabuntus created just for very old low resource systems. It works very well and I have used it on 32 and 64 bit systems. It is also very fast. Emmabuntus Description

Emmabuntus downloads 32 & 64 bit

First make sure you're using a 32-bit version of the OS, since hardware made before around 2008 won't even support 64-bit code. If the computer has a 64-bit CPU but not UEFI, even most modern distributions should support booting using conventional BIOS, just make sure the .iso file you download does.

You can't just put the .iso file on the CD, DVD, USB stick etc's existing filesystem, you have to dump it bit-for-bit to the device. There's a ton of graphical front-ends, tools etc. to do this, but the most direct way to write the image to a USB stick is with the command:

dd if=yourfile.iso of=/dev/sdX

...where /dev/sdX is the device that appears when you plug the USB device in. It will normally be "/dev/sd" followed by a single letter (a physical storage device) but no numbers (those are partitions on the device) For example /dev/sda1 and /dev/sda2 are the first 2 partitions on /dev/sda whcih may be a hard disk, ssd, optical disk, USB stick, or whatever. You can see them appear in the output of:

dmesg -wH

While this command is running in a terminal window, (re)plug your USB stick. Then once you see it, make sure it's the correct one (very important!!) with:

fdisk -l

Just be careful not to nuke the partition table on any of your other drive(s) by writing to the wrong one!!