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Several times my Pi 4B has become unresponsive because I dropped a screw or a penny on it. The lights on the board stay on, but all other functions cease and I cannot reach it via SSH. Disconnecting and reconnecting power fixes the problem, however, pulling the plug could cause some problems.

Is there any way to reboot or shut down a hung Pi safely?

user118616
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1 Answers1

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If it has hung because you dropped something conductive on it (something that conducts electricity) which has bridged some tracks on the board, then one reason for not pulling the plug, the risk of file system damage, does not apply. If that was going to happen, it happened when the Pi froze. The other reason given in the answers you linked to, which is the risk of damage to the power connector, applies if you do it lots and lots, or if you are very clumsy. If it worries you, pull the power supply out of the wall outlet.

You should not be thinking "How can I restart the hung Pi safely?". You should be thinking "How can I make 100 percent sure this never, ever, happens again?".

You are very lucky that you have not destroyed the board completely, because dropping metal things on a powered-up computer board can very easily do that. You need to get a case with a lid, or put the board where you cannot drop things on it. You say this has happened 'several times'. You need to be more careful. Seriously.

Michael Harvey
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    "You need to be more careful." - or purchase a case ;-) – Ingo Apr 22 '20 at 17:21
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    Ignoring my stupidity, my original question was how to reboot an unresponsive Pi without pulling the plug. Is the answer “you can’t?” – user118616 Apr 23 '20 at 15:58
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    The answer is, indeed, 'you can't'. Raspberry pi boards do not have a reset button capability. While it is possible to wire a button to certain GPIO pins, and have a running service check for a press, and run a shutdown or reboot command, a hung system will not be able to do this. – Michael Harvey Apr 23 '20 at 16:27