I have a Pi Zero W, and I want to plug in a USB drive and use it as a tiny little backup server. I have a USB OTG cable, and when I plug in a flash drive (later I hope to use a much larger external hard drive), I get this in /var/log/kern.log:

Apr 19 23:06:04 pizerow kernel: [175237.013379] /dev/sda: Can't open blockdev

If I do sudo mount /dev/sda /media/myuser, I get:

mount: /media/myuser: special device /dev/sda does not exist.

This same USB flash drive works fine on a regular laptop running Ubuntu; it mounts without trouble.

Is this something with the USB OTG setup? With the block devices? Do I need to use some other device?

1 Answer 1


This isn't a very satisfying answer, but everything seems to work if I have the USB drive plugged in before booting, and then mount it.

If I unmount, remove the drive, plug it back in, and try to remount, then it does not work.

Fortunately for my use-case I plan to have an external drive plugged in all the time, so this will be fine, but anyone reading this who wants to unplug and later reconnect devices...I still don't know how to make that work.

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