This allowed users to install hard drives larger than 137GB, a massive upgrade during an era when 200GB+ drives were becoming affordable.
There is no official Microsoft kernel 4627. This suggests one of three possibilities:
In the modding scene, "Complex" wasn't just an adjective; it was a brand. was a legendary group in the console underground. They were famous for releasing "BIOS hacks"—modified versions of the official Microsoft kernel that removed the security checks.