avoid Lethal Labyrinth system prompt

src/prelaunch/lethal.kbd.a

@@ -51,17 +51,16 @@ callback2
 
 ++       cmp   #3
          bne   +
+         sta   $39
          lda   #<callback3
          sta   $38
-         lda   #<callback3
-         sta   $39
 +        clc
          rts
 
 callback3
-         lda   #$81
+         lda   #$1B
          sta   $38
-         lda   #$9E
+         lda   #$FD
          sta   $39
          +READ_RAM2_NO_WRITE
          bit   MachineStatus

src/prelaunch/lethal.labyrnth.a

@@ -1,5 +1,5 @@
 ;license:MIT
-;(c) 2021-2022 by qkumba
+;(c) 2024 by qkumba
 
 !cpu 6502
 !to "build/PRELAUNCH.INDEXED/LL",plain