Document changes.

bitsy.boot.s

@@ -2,13 +2,22 @@
 ; Created: 2023-09-07 02:57:20
 ;
 ; Stock BITSY.BOOT doesn't reliably work on my Franklin.
-; It appears that the check for an open-Apple keypress on a pre-//e isn't
-; reliably low/high -- same issue as console5's gamepad adapter.
 ;
-; Defining PLUS_FIX at compile time moves the check for O-A to the end of the
-; keypress matching routine.  This does the right thing on my Franklin; I don't
-; have a //e to test with, but the logic should be sound.  And it only costs
-; two extra bytes :)
+; Because the open-Apple key is wired into the game port, machines without
+; that key will falsely report that O-A is pressed when RDBTN0 is read.  That
+; effectively prevents booting from any slot, as O-A was tested first and
+; thus branches to the GS/OS exit logic.
+;
+; Re-ordering the command key logic so that valid slot boot attempts are 
+; processed before O-A is tested results in a working BITSY.BOOT.  While I
+; was there, I eliminated redundancy and use MACHID to skip the O-A check on
+; machines that don't have it (][, ][+, and clones thereof)
+; 
+; This doesn't fix all cases -- MACHID doesn't distinguish between a //e with
+; clock card and a IIgs, so hitting O-A/Q on that //e will crash the machine.
+; So it goes.
+;
+; -- Chris RYU, 07 September 2023
 
 .macpack apple2
 .setcpu "6502"