Boot issue fixed between 2.02 and 2.04; what changed?

[James Cook]

First, some context:

I'm hoping to find a minimal patch to Grub 2.02 to fix a boot issue on
the the latest release of the NixOS distribution. Grub 2.04 fixes the
issue, but some users had trouble with it, so backporting 2.04 might
not be a good idea.

I'm asking this in case someone can think of something obvious to try.

The symptom:

When I try to boot my laptop (Dell XPS 7390 Developer Edition) with a
USB stick with Grub 2.02, the laptop freezes. Specifically, when I
choose the USB stick from the BIOS, or use "chainloader
.../efi/boot/bootx64.efi" and then "boot" from a working Grub
installation, whatever is on the screen (the Dell logo, or the
commands I typed into the first Grub, respectively) stays there, a
text cursor appears in the upper-left corner, and the laptop's fan
eventually turns on.

The question:

Any idea which change between 2.02 and 2.04 might have fixed this? If
anyone could suggest, say, 6 likely changes I could try patching, I'd
love to try them and see if one of them fixes the issue.

James