Getting errors when I shutdown when my hard drive is connected.

alftheelf · January 30, 2023 at 2:49 PM

I'm running LibreELEC 19.5 on my raspberry pi 3.

When I shutdown/reboot I get errors:

Failed to unmount /flash: Device or resource busy

systemd-shutdown[1]: Failed to finalize file systems, loop devices, ignoring.

It seems to only do this when my main 1TB hard drive is connected. If there is no drive attached it's fine, and when I connected another usb drive it didn't cause errors either.

Because it says Failed to unmount /flash, I thought this was probably to do with the fact I've added support for an IR controller. In doing so, I had to mount -o remount,rw /flash, edit the config.txt and then mount -o remount,ro /flash. However I took another identical microSD card and started fresh with a new image of LibreELEC without configuring the IR, using only a usb keyboard, and the same errors happened when I shutdown.

When I try to unmount the hard drive with umount /dev/sda1 it still produces the errors until I physically pull it out of the usb port. Then it shuts down ok.

If I run df -h, I can see that /dev/mmcblk0p1 is mounted on /flash. When I try to unmount it, I get umount: can't unmount /flash: Device or resource busy.

What's could be this to not shutdown correctly?

**HiassofT** · January 30, 2023 at 4:38 PM

You can safely ignore the "Failed to unmount /flash" message, that's normal, but the "under-voltage detected" message indicates a serious issue:

Use a better power supply (the official RPi one is highly recommended) and/or a powered USB hub or USB drive.

so long,

Hias

alftheelf · January 30, 2023 at 5:19 PM

Quote from HiassofT

Use a better power supply (the official RPi one is highly recommended) and/or a powered USB hub or USB drive.

I was using a 2A USB adapter at first. When I use it with Raspberry Pi OS, it shows the lighting bolt symbol. After seeing the "under-voltage detected" message I switched to use my iPad's 2.1A adapter and still got the "under-voltage detected" message.

Why does it say under-voltage, and not low current? I can trust my iPad charger is outputting 5.1V. Would this message appear if they current is too low. You think I need the 2.5A to work with my hard drive?

**HiassofT** · January 30, 2023 at 5:23 PM

It says undervoltage because it checks if the voltage on the RPi PCB dropped below about 4.75 volts - which will usually "upset" USB devices but can lead to all sorts of problems.

Don't use any charger, use the official RPi power supply and if that's not enough (RPi can only provide a very limited amount of current to USB ports) then use a powered hub or drive.

so long,

Hias

**blueribb** · January 30, 2023 at 5:24 PM

It will say "under-voltage" when the current draw is exceeded. Voltage drops when too much current is used. Use the official RPi power supply as recommended.

Edit: Hias beat me to it ☺

alftheelf · January 30, 2023 at 7:42 PM

Quote from HiassofT

Don't use any charger, use the official RPi power supply

Will the 3A supply be better for my usb hard drive than the 2.5A supply? Pi Hut doesn't say the 3A is compatible with the RPi3B. I don't understand why it wouldn't be ok to use. I don't want to get the 2.5A and find it's still not enough current when both are the same price.

**HiassofT** · January 30, 2023 at 8:05 PM

For RPi0-3 you have to use the 2.5A one (with a micro USB plug), the 3A one is for RPi4 only (with a USB C plug).

RPi's can't provide more than 1.1A total (!) on all USB ports and the 2.5A is sufficient for that.

so long,

Hias

alftheelf · January 30, 2023 at 11:27 PM

Quote from HiassofT

For RPi0-3 you have to use the 2.5A one (with a micro USB plug), the 3A one is for RPi4 only (with a USB C plug).
RPi's can't provide more than 1.1A total (!) on all USB ports and the 2.5A is sufficient for that.
so long,
Hias

Awesome. Thanks for your help. 🦄

Getting errors when I shutdown when my hard drive is connected.

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