I want to know the answer to the following question:
What was introduced that made using Mac OS alternative operating systems easier?
All the background I'm provided with is that "Used even by Apple for A/UX and MkLinux, this technique is no longer necessary since the introduction of Open Firmware-based PCI Macs, though it was formerly used for convenience on many Old World ROM systems due to bugs in the firmware implementation.[citation needed]". Is that enough to answer the question?