That's obviously badly phrased.
The far jump is obviously required on all CPU's in order for us to
actually finally get to 32-bit protected mode and reload CS, but what I
*meant* was that we certainly also know that "unreal mode" works and is
used by various strange DOS extenders, and that not doing the far jump
isn't really required for having a "working setup" - it's just going to be
a rather limited mode.
So the short jump is required for the code to *work*. The long jump is
required only to get us the 32-bit mode we *want* and out of the odd
"half-way" state. Two different issues.