The (rd) is not a BIOS drive( it is only a grub4dos drive). It would be invalid and would disappear when ntldr/bootmgr gains control. So the chainloader command decides to not use it. This is understandable.
Yep , now that you have explained it, it is understandable .
TEST 1: Error 14 and HANG ------ this should be a bug introduced recently. Try older versions.
TEST 2: failed to set the boot partition for ntldr/bootmgr. This should also be an introduced bug. Try version 0.4.4.
Naaah, there is no need/utility in testing on other versions, the theme was how to use the old 0.4.3 2007-10-15 version that Spyhunter uses renamed as shldr (and not any other version), i.e. finding a way to have the poor chaps that found themselves into a non-booting situation manage to boot again their botched system, the tests were performed on that one.
With a newer version the (complicated and convoluted ) trick of using a "partitioned" (rd) works as well, but the point was to help the people that are stuck in that non-booting loop to exit it even if they did not have a Windows DVD/iso or an USB stick (or for whatever reasons they could not boot successfully from them).
The --edx=0x0080 trick works nicely with that old version and presumably it will work on any newer one, we just had a report of an user that fell in a similar (but this time not related to Spyhunter) trap, and your suggestion worked fine:
as said, simple and effective