Pendrive boot with legacy BIOS

Hi, I want to install EndeavourOS to an old, but not so horrible pc, but the BIOS wont boot from pendrive.
Currently Manjaro is running on the pc, which I installed through pendrive, and I wrote the pendrive via Rufus (it has some extra options for bios support, but It doesn’t seem to work now), so I used the dd command, but the BIOS just refuse to detect an OS on the pendrive.
Is there any way to make it work with the pendrive, or my only option is to write a DVD?

you should check your Bios Settings, and clear if the old PC is a legacy system or UEFI, if it is UEFI you should check if there is set something related to usb handling like legacy-usb.
Rufus burning will only work in ISO mode or DD mode if you set anything what will change the way the ISO boots (any setting in Rufus efi and Bios) it will cause issue.
The ISO is ready to boot like it is for UEFI or legacy-Bios and also for usb and DVD.

When I installed EndeavourOS from my pendrive, I failed with the dd command, too, and succeeded with Ubuntu’s Startup Disk Creator (usb-creator). I think I also converted the file endeavouros-2021.02.03-x86_64.iso into endeavouros-2021.02.03-x86_64.img before writing it to the pendrive.
Maybe this helps you a bit, too.

It’s award BIOS from 2007, I’m 100% sure it’s not UEFI.

I will try but, my UEFI pc can boot from the pendrive.

does the PC see the USB stick at all? or can you choose it from bootmenu (F12) and it does not boot then?

It’s only has an usb hdd option, which I used back in the day to install windows 7, and a few months ago to install Manjaro.

do you try different usb ports already?

Is it possible that the pendrive is using gpt partition table, and thats causing the issue? If I use gparted and create an ms-dos table, then I format the pendrive to fat32, and copy the contents of the iso to the pendrive, will it work?

Yes.

I used mint stick, from AUR and that works on all my devices, dd works on some and etcher works on some but mint stick works on all. Maybe worth a try.

The ISO is fully compatible with legacy-Bios systems and an ISO has ISO filesystem (iso9660),
Partitioning is MBR and not GPT.
This is a so called hybrid ISO-file.

The alternative to workaround your issue could be to use ventoy, as it will create a boot menu to select any ISO file you can copy to the stick.

aur/ventoy-bin 1.0.38-1 (+61 9.84) 
    A new multiboot USB solution (Binary)

It is on AUR and once installed on the pendrive you can simply copy ISO on the pendrive, boot ventoy and select EndeavourOS from ventoy menu to boot the ISO.

When you say copy the contents of the ISO? You should be able to create the live iso on the usb pendrive with popsicle or etcher-git. If you have manjaro still you should be able to install one of these apps and create the live ISO on the pendrive.

Thank you, I tested ventoy on a really old laptop with BIOS, and it worked, but I currently can’t test it on the said pc, but once I’m able to, I will update the post.