KO7I nRST Qi | KO7O Qi+1
-------------+----------
X L X | L A after reset, lock KEYOUT7 low (1)
H H A | L A stay locked while KO7I is high
L H A | L B KO7O tracks KO7I after first L on KO7I (2)
L H B | L B (3)
H H B | Z B note that KO7O is open collector/tri-state (4)
(1) possibly equivalent alternatives:
X H->L X | L A
X L->H X | L A
(2) equivalent alternative:
H->L H A | L B
(3) equivalent alternative:
H->L H B | L B
(4) equivalent alternative:
L->H H B | Z B