Can USB loader GX accss GUID drives (or only MBR ones)?

Hi

I very recently hacked my Wii using letterbomb and did a bunch of other things following tutorials, including installing the HBC and USB Loader GX.
I connected an external USB drive (3TB, GUID, 3,5'', self-powered) onto the outer most USB port of my Wii. This drive was formatted as FAT32 in macOS.

The ROMs I have are compressed (7z/zip) files containing either iso or wbfs. Thus I created a wbfs folder at the root of my USB drive and moved my wbfs files into it. AFAIU, I need to convert/import iso games into wbfs format first in order to play them, right? (I wish games could be read as compressed files like in emulators )

Now, when I launch USB Loader GX (ULGX), I get the channels displayed instead of the games. ULGX cannot initialize my USB drive apparently.

So I changed 2 things (I know, bad methodology...), I used another drive (500GB, MBR, 2,5'', USB-powered) also formatted as FAT32 and copied my files onto it.
Then, ULGX could see the games on the drive and I could play some of them (some others just make ULGX crash and then I'm back to the HBC, but this is another topic...).

I'd really like to use a larger drive rather than a smaller one. So my question is: Is GUID a no-go? Are we limited to 2TB in ULGX due to MBR limitations?

Thank you very much in advance for your help.
Best,
-a-

 

Shoot!
Can anyone confirm that? Or is this referenced in some sort of documentation (if any exists)?
Thanks for your very rapid reply