I own a raspberry pi model B revision 2 and when I switch it on, it gives me the following error message:

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

I researched through the internet for a solution but the same message keeps showing up.

I edited the file recovery.cmdline and appended the word disablesafemode at the end like this:

quiet vt.cur_default=1 coherent_pool=6M elevator=deadline disablesafemode

But no success.

The sd card is not faulty because I have tried it in another raspberry pi and the noobs loads up with no problem.

Could you please help me? Thank you very much for your time.

1 Answer 1


After reading several posts, I decided to install the raspbian jessie in a sdcard and insert it in my raspberry pi 1 model B. This time the raspberry pi managed to boot successfully but the usb ports do not seem to work, the mouse and keyboard do not function at all.

Therefore I thought to connect to the raspberry pi remotely by using putty. Since the usb ports do not function, I could not use a wifi dongle, so I used an ethernet cable to connect my raspberry pi directly to my router. Unfortunately it doesn't seem to connect either because I am not able to view the raspberry pi connection on my router control panel.

Please note that: I have read in https://elinux.org/RPi_Hardware#Power_supply_problems about the polyfuse issue, and measured the voltage between TP1 and TP2 to be 5.51 volts, way above the range between 4.75 and 5.25 volts.

If you think you have a problem with your power supply, it is a good idea to check the actual voltage on the Raspberry Pi circuit board. Two test points labelled TP1 and TP2 are provided on the circuit board to facilitate voltage measurements. Use a multimeter which is set to the range 20 volts DC (or 20 V =). **You should see a voltage between 4.75 and 5.25 volts**. Anything outside this range indicates that you have a problem with your power supply or your power cable, or the input polyfuse F3. Anything inside, but close to the limits, of this range may indicate a problem.

So there must be an issue with the input polyfuse F3. Bypassing the polyfuse with a thin wire, will it solve the problem? Or do I need to replace the polyfuse F3?

Please help me and thank you very much for your precious time.


  • Please accept your own answer with a click on the tick on its left side. Only this will finish the question and it will not pop up again year for year.
    – Ingo
    May 14, 2020 at 11:54

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