Suppose I have a PC with a working boot loader and OS X partition on its internal drive.
The disk uses MBR partition scheme, meaning that the Extra folder is located on the OS X volume.
Now, suppose something is wrong with the setup in that Extra folder, e.g. a bad extension is installed there, causing trouble, or the Boot.plist is bad.
So, I thought: I'll simply install another boot loader and Extra folder onto a separate disk (i.e. a USB memory stick), tell the PC BIOS to boot from that external disk, and once that disk's boot loader comes up, I choose to continue booting from the PC's OS X partition.
Now here's what I hoped would happen but which didn't:
I expected that the boot loader would take the files from the Extra folder on the USB stick. But instead, it took those from the OS X partition, running in the badly configured Extra folder again.
I thought this was a valid expectation because as long as the OS X partition has no Extra folder and boot loader installed yet, the Extra folder from the USB stick will be used. Secondly, as a general rule, the order to precedence should always be to prefer the more specific (here: USB stick where I explicitly start up from) over the more general (the default on the booted OS X volume), agreed?
So, what I'm asking here: Is there a way to set up the USB stick so that its Extra folder precedes or replaces the one on the destined OS X boot volume? If not, would a feature request for this make sense?