Dell E7450

I have an old Dell Latitude E7450 with 4GB of RAM, and I’m playing around with Liam Proven’s Github project for booting from a USB key into a SvarDOS distraction-free writing environment; it works just fine.

But unlike every other laptop I've tried this on (including Asus and Purism laptops), instead of showing 640KB or 639KB free DOS memory after booting to SvarDOS, the E7450 shows only 581KB free. Something on the E7450 is grabbing 59KB of RAM in the first megabyte before any drivers or memory-resident programs are loaded.

Anyone now what's grabbing that 59KB on the Dell, and if there's a way to stop it from doing that?

Thank you!