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I have recently set up a Plex Media Server on a new Raspberry Pi 4 (4 Gb).

This is powered using it's own official power supply, the Pi is connected via USB to a powered USB hub which has a 1TB WD MyPassport HDD attached.

Here is the powered USB hub.

Here is the External HDD.

The issue is, when I do a sudo reboot of the Pi, the Pi does not reach the Debian Desktop.

If I unplug the HDD physically, it boots just fine and if I plug the HDD in after it's booted it runs perfectly well.

I don't think this is an issue with my fstab set up as the HDD mounts automatically and can be read from perfectly once connected, the Pi just doesn't reboot.

I have tried unmounting the HDD before reboot but no luck.

sudo service plexmediaserver stop lsof /mnt/RasplexHDD sudo reboot

I have a feeling that the Pi is attempting to power the HDD when it boots, when the Pi reboots I only get a blank screen with a blinking cursor which also happens when powering the Pi with insufficient power. (Despite the Pi running from it's official power supply and the HDD being powered by a powered USB hub which is plugged into the mains)

Ideally, I would like it so when the Pi is being rebooted, the HDD spins down and only starts back up after the Pi has already booted from the SD card.

Please let me know if you need any more information than this.

Thanks for your help.

Edit: Just thought if there was a way to delay the USB from starting or delay the HDD being read until the Pi has fully booted that might work?

Edit2: Bit of extra information, I tried rebooting the Rpi with the powered USB hub still attached but with the HDD detached completey and the Rpi booted fine, so I think the USB hub isn't causing any issues.

Scott Wilks
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  • I know My 2TB HDD's idle/spinning current is around 170mA. The thing is when you power up Rpi and HDD at the same time, the HDD motor might take a start current many times of the steady/spinning state current. My get around is only switch on power and mount the USB HDD when I want to do backbup, and unmount afterwards, You might like to read my answer to the post: https://raspberrypi.stackexchange.com/questions/100353/can-the-3b-power-two-usb-ssd-drives – tlfong01 Jul 12 '19 at 14:01
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    Hi @tlfong01 Thank you for your reply but I'm not sure if it's what I'm looking for, my HDD needs to always be attached due to storing media for Plex, I just want to be able to reboot the Pi with the HDD still attached so I can reboot the Pi remotely. – Scott Wilks Jul 12 '19 at 14:44
  • Scott Wilks, I see. So your HDD is not for casual backup, but continuous media applications. Therefore auto boot is a must requirement. Now I see that you power hub charger port is only "up to 2.4A". This is a bit marginal to supply power to both Rpi and a HDD. I would suggest you to upgrade your PSU to 3A, or 5A. – tlfong01 Jul 13 '19 at 04:18
  • Hi Scott Wilks, There are at least two other work arounds (1) Separate power supply for HDD: https://rcbeacon.com/blog/?p=1777 (2) Delayed after boot bash script to auto mount HDD, (3) Add a big bypass capacitor near Rpi micro USB power connector (I actually use a huge 10,000 uF one!). – tlfong01 Jul 16 '19 at 04:07

2 Answers2

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I ended up solving this by soldering in diodes in the usb cable. I wanted to run a dual HDD USB RAID NAS but the boot failure (back powering issue) got me flummuxed for a bit. Didn't want to use try usb hub (party for speed reasons - hdd would be connected through two usb hub chips inc onboard one). I used the split power cables from ebay - feeding the non-USB3 plugs with 5v from separate 3A supply and soldering in diodes in the 5v line in the cable. Be sure to make good the sheilding after. Now works great. enter image description here enter image description here enter image description here

Dave R
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  • That is some dedication. What diodes did you end up using? – Math1000 Jun 01 '20 at 06:25
  • This is an elegant solution, though I think it is also overengineered... I do use those splitter cables as well, and my quick and dirty solution is to just cut off the 5V/GND line between the raspi and the disk, so power only goes from the external supply to the disk, and only data goes to the raspberry. I pondered about leaving the GND cable alone, as to have a GND reference between HDD and raspi, but that isn't really necessary, as the data+/data- cables are their own reference. – ephestione Jan 27 '21 at 09:28
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Same problem here. A Pi4 will not reboot if a powered USB 3.0 hub with HDD is connected.

I have opened up a cheap Chinese USB 3.0 hub, and de-soldered the red 5V power cable to the computer, so, this one will always need external power to work, and it does. But the Pi4 will not reboot while it is connected. This indicates that the problem is not back powering from the HUB to the PI.

I have, however, found two hubs that work fine. The Pi4 will reboot with one of these connected and powered externally. They are both from a Chinese company called Ugreen. One is a USB 3.0 hub with gigabit Ethernet added, "Ugreen Model: 20265". Everything works with this one attached, including Ethernet. The other one working is "Ugreen Model: 20291" I also bought another USB 3.0 hub marketed under the label Ugreen, but this does not work, and there is no model number sticker on it, only the letters "UGREEN" embossed on top of it.

Many other USB 3.0 hubs I own work OK, but the Pi4 will not reboot when connected to one of them with external power and a HDD. If they are unplugged, the Pi will reboot, and then the hub can be reconnected and all works fine.

Hallgeir Lied
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  • Please consider removing the last 3 paragraphs of your answer: they don't address the question at all and just describe the setup you have and the reasons that made you buy a Raspberry. – Dmitry Grigoryev Sep 26 '19 at 08:57
  • Hi, sorry for the late reply but I have decided to buy a Ugreen Model: 20265, I will report back with results soon. Thanks for your help. :) – Scott Wilks Jan 29 '20 at 09:26