You certainly deserve a break @PulkoMandy given the amount of posts you contribute 
Should I figure out how to get a bug fix ticket into Haiku about the failure of Haiku DriveSetup to set Partition Type to Be File System either when it formats a partition, or by the GUI menu option which indicate it should (but it doesn’t). Getting around that “bug” is the core of the whole procedure I posted and it would not be needed if that “bug” did not exist. It is the brick wall you hit. Without the “bug” UEFI Booting Haiku | Haiku Project is guide enough.
This “bug” thwarting many installs attempts, was previously discussed two years ago per the details below
waddlesplashDeveloper
This sounds like a bug we should fix. Is there a ticket about this yet?