For the homebrew community, this was a declaration of war. The BIOS was now the enemy.
It was meant to be a minor patch to add 3D support and PlayStation Store tweaks. But in the rush to push features, the engineers left a debug mode open. Specifically, the BIOS allowed the installation of package files (.pkg) from external media without proper signature verification. ps 3 bios
In almost all cases, when someone asks for a "PS3 BIOS," they are actually looking for one of two things: For the homebrew community, this was a declaration of war