On 13/09/2020 17:30, NY wrote:
> I have an Atolla powered USB hub
>
https://www.amazon.co.uk/gp/product/B07B2HJG8P/ref=ppx_yo_dt_b_asin_title_o03_s
01
>
> which I bought to power a spinning HDD that I plugged into my Pi 3B+.
>
> I'm now using it in my Pi 4B. If the Pi is rebooted without shutdown and
> power-off/on, it boots fine. However if it is shutdown and then the
> power is
> removed and replaced (whether that is immediately or half an hour later)
> the
> Pi refuses to boot: the green LED does not come on and nothing appears on
> either HDMI output. If it is in that state and I unplug the hub, booting
> continues immediately, even if the hub is replaced immediately after being
> removed.
>
> Has anyone some across this incompatibility? It's a bit of a bummer because
> it means the Pi will not auto-start in the even of a power-cut - unless
> I am
> present to remove/replace the hub.
>
> It is related to the hub rather than what is plugged into it. It happens
> even if the HDD and other devices are removed from it. Removing the
> power to
> the hub is sufficient to allow booting: maybe I need some means of making
> the mains to the hub delay coming on for a few seconds after power it
> supplied to the Pi!
>
> I'm wondering whether to buy a different make of hub, or whether I may find
> that this is affected in the same way.
>
> Does anyone know of a make of powered USB3 hub which is known to work
> with the Pi 4 after power-cycle?
>
>
>
> This is separate to the /etc/fstab auto-mount problem that I posted about
> yesterday. In that case, the Pi would *start* to boot and then fail at
> mount
> time; in this case there is no sign that the Pi is even beginning to boot.

Known problem:

https://www.raspberrypi.org/forums/viewtopic.php?t=244900

One fix is to snip the red wire in the cable between the hub and the Pi.
--
Dave

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