I have a new Raspberry Pi with Raspian Wheezy installed and has several cables connected to it via the GPIO pins. However, I noticed if I have anything connected to them during boot up, the device fails to boot, and prints:

sh: can't access tty: job control turned off
/ #

If I disconnect the cables from the GPIO and power on, the device boots just fine, and I can use the GPIO pins. However, I would like the device to be able to do a complete reboot without me having to manually disconnect the GPIO every time it is starting up.

Is there some why I can leave the GPIO cable and it communicating device connected while it performs a boot?

Here is some discussion for the Raspberry Pi forms: http://www.raspberrypi.org/forums/viewtopic.php?t=60412&p=451108

Thank you for your time.

  • 1
    If you want help you'll have to say precisely what you have connected to each gpio during boot.
    – joan
    Commented Jun 18, 2014 at 21:17
  • Depending on what you have connected, your RP is thinking it can boot from there. However, the error message you get is not consistent with not booting, it seem that you have shell right there? Because, usually that error message is only displayed when kernel and new shell is not able to allocate a pseudo-terminal.
    – not2qubit
    Commented Jul 2, 2014 at 18:09

4 Answers 4


Try adding avoid_safe_mode=1 to config.txt as told here:


The problem is your device is jumpering those pins and you're seeing the safe mode shell (it did boot). This has apparently been disabled with newer firmware.


I know it is a trivial answer but... make sure all of your connections are secure (and correct). I got this error because a jumper cable had come loose.


Check your GPIO pin connectivity to your external devices. Pin misalignment leads to this

h: can't access tty; job control turned off

Internal pins are odd numbers and external pins are even, in the 40 pin RasPi B+ board.


My Raspberry Pi had the problem too, I even tried all other methods until directly loading the operating system on the SD card, (e.g Raspbian, Ubuntu Mate, etc) Simply write to the SD card with Win32DiskImager (Don't worry it works on other media too!) on source forge. (Win32DiskImager Link-http://sourceforge.net/projects/win32diskimager/) This Could Help!

  • 1
    How does this help the OP? Is it that it takes away the NOOBS system so there is nothing that checks for the GPIO pin 5 state on boot up?
    – SlySven
    Commented Jan 12, 2016 at 1:54

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