GRUB gives 'Illegal instruction' error on start

[html] Hi all!

I’m trying to add a static build of grub to an embedded system I am experimenting with. For this purpose I am using the grub executable from a static build that Gentoo provides.
However, when I execute this build on my target system (also x86), I get:

Probing devices to guess BIOS drives. This may take a long time.
Illegal instruction

Do I need more than just the grub executable? I’ve tried adding the /lib/grub directory contents as well, but I still get this error…