#119 Document UEFI limitation and mention Ventoy for USB
First of all, thanks for FreeDOS. I am glad it exists.
Recently, I had to prepare a FreeDOS boot USB stick in order to upgrade the firmware on a Samsung hard disk. It was a much harder task than I thought, I had to read a lot of to figure it out.
In order to prevent wasting some other people's time, I think the FreeDOS website should mention prominently that FreeDOS does not boot in UEFI mode. I only found out through other people on the Internet.
I would guess that most people do not boot FreeDOS only to run the software it bundles, but to run some other software. In my case, it was a firmware updater written by the hard disk manufacturer. I am also guessing that most people will not want to install FreeDOS, but to run it off an USB stick, as CD-ROM drives are slow and no longer omnipresent .
The trouble is, the FreeDOS website does not say how to make an USB stick or how to add your own files, and making a custom FreeDOS image with your own additional files is hard.
I tried writing the ISO file from the "FreeDOS 1.3 LiveCD" to a USB stick, but my BIOS wouldn't boot from it. I guess it is because of the ISO 9660 format.
The download page has a "FreeDOS 1.3 FullUSB" which mentions a "USB fob" (strange term), but alas, there are no instructions about how to actually write a USB stick. By the way, file "FD13FULL.VMDK" is not really a "virtual machine disk file", but a configuration file for the .IMG file (not everybody is familiar with such files).
Fist of all, I think the FreeDOS website should mention that, if you need your own files, an easy way is to use a second USB stick formatted with FAT32.
I would also mention the following way, which I found much better: create a bootable USB stick with Ventoy, delete and recreate its exFAT data partition as FAT32, and then place the FreeDOS CD-ROM ISO image there, together with your own files. Then make sure that Ventoy starts in BIOS (not UEFI) mode, and finally start FreeDOS from Ventoy's start-up menu. The whole FAT32 data partition with your own files will be accessible from inside FreeDOS.
Well any DOS that is compatible to MS-DOS requires BIOS support. It's not possible to run a DOS system without a real BIOS or on UEFI motherboards without LEGACY BIOS mode support. The same applies to FreeDOS and FreeDOS can't change that.
But i agree, it's a good idea to mentioned at a prominent place, for example the download section, that FreeDOS requires a BIOS or Legacy BIOS and will not run on only UEFI computers.
The easiest way in my opinion is to mount the USB stick in a virtual machine as hard drive and then booting the FreeDOS ISO image inside the virtual machine. After that, you can install FreeDOS on the USB stick.
This requires virtual input/ouput support on the hardware side of the computer. AMD-Vi or VT-d.
https://en.wikipedia.org/wiki/X86_virtualization#I/O_MMU_virtualization_(AMD-Vi_and_Intel_VT-d)
And the virtual machine software must be able to support mounting a real USB disk inside a VM.
QEMU does support this. I wasn't able to do this in Virtualbox, but it's been a while since I last tested it with Virtualbox. A newer version might do the trick.
The best thing would be if you could download with FreeDOS pre-configured USB disk partitions right away, which you then only have to copy to the USB stick using a suitable tool. Just like many Linux distributions do today.
And Fat32 is useful in case some firmware update tools use long filenames. A second partition would also be sufficient here. And of course no GPT partitioning table may be used.
Last edit: Oliver 2023-07-21
We're working on an update to the website (new design, etc) and I'll try to make this more clear in the "download" section.
Like any DOS, FreeDOS requires an Intel CPU and a BIOS.
That's not true. FreeDOS works perfectly on x86 CPUs from AMD, Cyrix, NexGen, National Semiconductor, NEC, UMC, IBM, SIS, Siemens, Harris Corporation and many others.
Here's a list:
https://en.wikipedia.org/wiki/List_of_x86_manufacturers
FreeDOS requires only a x86 compatible CPU and a IBM PC compatible BIOS.