anticapitalX
I don’t think I understand your question and how to solve it? I don’t use virtualbox, so I don’t understand the context of your question. Perhaps other users who use virtualbox and grub would have an answer for you.
i don’t understand their question either .
but with installation of the previous iso published by you, I had trouble installing grub .
this was how I managed to install grub
https://www.antixforum.com/forums/topic/antix25-xfce-sysvinit-trixie-stable-respin/page/3/#post-191422
but it was only that time grub wasn’t installed.
after upgrading system , and remastering it , grub never failed to install for me again .
look at what I did . it maybe useful for you in virtualbox or whatever environment your trying to install XfceOnlyantiXtrixie
Let's accept antiX as it is
Pure and Elegant by its nature