Bios Upgrade?

Unfortunately, this system can not be upgrade to UEFI firmware.  The latest BIOS was released in 2010.  Download to your desktop and run update if needed.  But it won't support UEFI.  

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=p9j9h&oscode=w764&productcode=inspiron-580

@Chino de Oro​ There must be some unofficial workaround. I honestly don't care if it reports as the correct system. I.e. Dell Inspiron 580. As long as it works, I'll be happy.

It can report as an apple ii or a Swiffer for all I care. I'm never going to claim a warranty. It survived a fire and was free to me.

I'm the kind of guy that used to swap bios chips, back in the day.

Unless there is some other hardware limitation that prevents it. There must be a way.

What do you hope to achieve by searching for way to change BIOS to UEFI?  They are the same, UEFI is just a modern BIOS and can offer more features which your system board does not have nor support.

This machine was made years before UEFI firmware being implemented on Dell PC.  As you said, you just need a working machine.  The system should work well with its BIOS.

It may not be the same comparison, but if an engine was designed to run with carburetor.  It does not have to be modified to take electronic fuel injector, a newer type of fuel delivery to engine

@Chino de Oro​ I have worked on many engines. Most have benefited from a fuel injection upgrade. Swap a few parts and I can even put in direct injection.

I've run Jeeps on Chevy and Ford parts. I'm the last person that would say doing something to a vehicle is impossible. There are always workaround for what needs to be done. Some crude. Some elegant.

Case in point. I have win 11 installed. I have upgraded the GPU. And CPU. I have DDR4 RAM Now.

What I'm lacking is the BIOS. I can't use larger drives.

I am doing things people told me were impossible on this system. And making them work well. I might add.

Someone, somewhere has modded the BIOS and I will fi d them.

Even if you can manage to change BIOS to UEFI boot mode, it does not change the specifications and compatibility support by the motherboard.  Not all today components will work with this 580.  But, you still can update this system for optimal performance. 

For storage, use a small capacity SSD for boot drive.  Then, adding a larger capacity hard drive as desire, go to Disk Management and use drive wizard to add and format it with GPT for full drive capacity access. 

For the CPU, this system is limited to Core-i first generation and a few Xeon, Lynnfield processors.

For the memory, your DDR4 RAM will not work due to CPU limitation.  Maximum support is DDR3 1333 Mhz.

For GPU, select graphics card that suite your needs and consider performance limitation by PCIe Gen2 slot and CPU bottlenecking.

For operating system, Windows 11 could be bypassed and be installed on unsupported hardware.  However, none of the new features and security offered by Windows 11 will be function properly due lacking of support hardware.

Unlike collector items or restored classic automobile, there is no return value for your time, effort, and money spent on this computer upgrade.  Just restore it to a working condition with any parts you might have.  Since you have it for free, don't waste money on it.

580 has H57 chipset, same as XPS 8100, LAG1156 socket

UEFI cannot just be added to a BIOS. The BIOS has to be developed using UEFI base code.