yeah, unfortunately when I looked into this a while back, there was quite a lot of anecdotal evidence/discussion and not a lot of clear facts
here’s what I understood , which as I say is incomplete…
it’s unclear if this is really an ‘issue’ of the hub or the motherboard, as it can be prevented on either side - it is not just just the organelle, and rPI, you see it on many other boards too, and Ive seen it happen not just with ‘cheap hubs’, but also branded ones.
my guess is perhaps the spec is a little unclear on who’s (host or hub) responsibility it is to prevent this.
but it does seem to be ‘undesirable’ behaviour (usually!) ,
- when both the device and hub is powered, a little current will flow back, that’s not desirable, but unlikely to cause issues.
- when the device is off and hub is powered, then this is when we see the ‘issue’,
mostly like the cause is the 5v line of the usb is connected directly to the 5v power line.
as such, I don’t think this should cause a problem if the device is powered by 5v, and the usb hub can provide enough amps.
In fact some have used this as a way to power old rPI… (hence why is say usually undesirable )
unfortunately the above makes a lot of assumption, and thats why we don’t get a definitive answer, and usually it ends up with ‘it depends’.
on the anecdotal side…
there are a huge number of rPIs in circulation (which have this ‘issue’),
I suspect a pretty large number of those have powered hubs connected (rPI has power issues of its own), I also bet a good percentage of these use cheaper hubs (given the rPI price point).
so, Id figure there are a very large number of rPI when backfeed occurs regularly.
given there is no huge outcry of blown rPIs, and they (rPI) have not sought to address it in newer models - my assumption is its pretty safe.
unfortunately, as said, this is incomplete and anecdotal
my approach has been - not to worry about it too much, try to power off my hub before rpi / organalle (if i remember). that said, this is just because I have some good quality usb hubs i reuse… and don’t see the need (or want) to replace.
I guess if i was buying a hub specifically for the rPI or Organelle, then why not buy a hub thats says it doesn’t backfeed… seems like a good idea, even if just for a bit of piece of mind.
disclaimer: Id not recommend intentionally backfeeding as a way to deliberately power your organelle, as if i do it, its for a very short while, when i notice I’ve pulled the DC power, and the organelle is still on