.syntax unified
    .cpu cortex-a7
    .thumb
    @ maze entry: return 0. Guard: bad lr (high byte != 0x08) spins
    @ with IRQs off instead of jumping into the void.
    .text
    .global maze_stub
maze_stub:
    movs r0, #0
    lsr r12, lr, #24
    cmp r12, #8
    bne maze_hang
    bx lr
maze_hang:
    cpsid i
    b maze_hang