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My Raspberry Pi Reboots on plugging in some USB devices. I do not think it is a power supply problem - I am using a 5v 30A power supply (ATX SMPS) and I have see it occur across two OS releases - (debian & Raspbian).

The devices I have used are EDiMAX WiFi dongle and RTL2832 USB dongle. Plugging in these device before booting works just fine.

What might be the reason for the reboot and how do I avoid it?

Lord Loh.
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1 Answers1

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Unfortunately, this is the expected behaviour. At least in newer RaspberryPi revisions, where USB polyfuses are removed (2.0 revision and some boards from revision 1.0). Since now there is (almost) no resistance on USB ports (to eliminate voltage drop), if you hot plug high power USB device, there will be sudden spike in current demand which may cause the reboot.

There are couple of things that could be done to prevent this but most of them involves hardware changes - bypassing F3 polyfuse, replacing capacitor, replacing 0R resistors at USB output, etc. There is, however, one simple solution (besides connecting USB devices before running Pi) - use powered USB hub and hot plug your devices to this hub instead of directly to RaspberryPi.

Krzysztof Adamski
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  • Wouldn't USB extension cable add some slight resistance and limit the inrush current? Or for that to have any effect it has be very long cable? – Marki555 Dec 01 '14 at 19:28
  • Typical 1m long USB cable will probably have ~0.25 - 0.5 Ohm resistance. I don't think this will make any difference. – Krzysztof Adamski Dec 02 '14 at 16:15
  • I have the same issue with the Zero4U USB shield (version 1.2) on a Raspberry Pi (non-W, version 1.3). This shield is powered by, and communicates over, pogo pins. Is the cause likely to be the same? – Luke Hutchison Jun 05 '19 at 04:25
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    I am curious whether the newer Raspberry Pi revisions (e.g. 3, 4) still have the same limitation. – Peter Bašista Apr 18 '22 at 09:00