I haven't been following all of the native boot discussions, but what I
remember was...

Sector zero of any disk is the boot block.  I think if the boot block
version number is setup correctly, execution will start at offset $8x in
sector zero and can do anything that we want.  This is before the "Welcome
To Macintosh" is displayed, and before the Finder or the System files are
opened.  The boot block is 12 or 16 sectors long.

See Inside Macintosh - Operating System Utilities - Start Manager - Page
9-6 for more information.

--
John D. Smerdon;  Livonia, Michigan, USA;  Contents are my opinion.
Home: jds@smerdon.livonia.mi.us