I don’t know to find the 3com 4500 firmware 3cr17561-91

HPe took over 3cpm in early 2010. These products were both EOS & EOL as in 2012. I do not think HPe support them any longer.

Using something this old isn’t going to be great. Is there any reason you can’t upgrade it?

Wayback machine? maybe?

Closest I can get to it is the main product page

But it looks like HP has lost some data as they claim there is no software for this switch when you navigate to the drivers page.

I can find release notes for the firmware so they definitely once existed, but it wouldn’t surprise me if they lost data when they went through their Aruba rebranding

If you’re having issues with it, then you might still be able to claim warranty, they might swap it out with a newer model, pretty sure those had lifetime warranty