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