title: How to turn USB port power on and off in Raspberry PI 4
body: <p>On a Raspberry PI 3B+, it's simple to turn power on its four USB ports off and on. Simply write a "0" to <code>/sys/devices/platform/soc/3f980000.usb/buspower</code> to turn power off and a "1" to turn power on.</p>
  
  <p>The same method doesn't work on Raspberry PI 4B, 4GB (the hex number before ".usb" is different, that's NOT the problem). I have tried <code>uhubctl</code> and <code>hub-ctl</code> as well without any success. I have used a USB power meter to measure the voltage on the ports. It doesn't change. Un a PI 3B+ it changes as expected.</p>
  
  <p>Does the PI 4 support turning USB power off and on in software at all? If it does, how to do it? Or is there a bug somewhere that has to be fixed to make it work? I use the newest Rapbian on both the Pi 3B+ and the Pi 4.</p>