Connection is the same as attaching an ordinary, "wired" HDMI Cable, except 
  that active cables can only be attached in one direction: One end of the cable 
  is specifically labeled for attachment to the HDMI Source (transmitting) 
  device, and the other end of the cable must be attached to the HDMI Sink 
  (receiving) device. If the cable is attached in reverse, no damage will occur, 
  but the connection will not work.

  HDMI Cables with HDMI Cable Power include a separate power connector for use 
  with source devices that do not support the HDMI Cable Power feature.

This is not your run-of-the-mill HDMI cable for sure.

No, not that feature. HDMI supported 5V/55mA power out for years. It's meant for EDID ROM chips and maybe HDMI selectors too, not Linux based computers, but some TVs could take it in gross violation of specifications and its spirits.

And the serial number of that power plug is MST3K-US

The first chromecast actually operated without external power, but it only worked with some TVs.

It's possible yours didn't provide enough power via HDMI, but at least ours worked just fine.

It is possible that your memory of a device from a decade ago is faulty. No Chromecast has ever been able to be powered by HDMI alone. That has never been a thing.

You may instead by remembering the fact only some TVs back then were successful at powering the Chromecast without an external power brick, using a USB port on the TV itself to power up the Chromecast.

In applications where this worked (and it often did work, although it also often did not work), it could provide a solution that existed entirely on the back of the TV with nothing additional plugged into the wall.

But it was still [micro] USB that provided the power to the OG streaming stick, not HDMI.

> It is possible that your memory of a device from a decade ago is faulty. No Chromecast has ever been able to be powered by HDMI alone. That has never been a thing.

It is not - I still use my 11yo Chromecast Gen1 today. And it still works fine without USB power (as long as you don't try to play YouTube videos).

Less than one hour before the Titanic hit an iceberg, I realized that I had forgotten my wallet and jumped off. I swam all of the way back to Southampton to get it.

This is probably not my most grand of deeds in my two hundred and seventy years, but it is nonetheless the most memorable to me on this fine Saturday morning.

I also had this device and would concur it was supposed to work without USB power, but in my experience worked extremely poorly.

"You may instead by remembering the fact only some TVs back then were successful at powering the Chromecast without an external power brick, using a USB port on the TV itself to power up the Chromecast."

I'm looking at my first gen plugged into the ARC HDMI port on my Vizio TV. It is ONLY attached to the HDMI port and nothing else.

+1 my visio powers this as well It also powers lots of stuff via usb

Maybe because it’s NOT a smart tv and doesn’t have some crazy android chip SoC to constantly power. I mean obviously you can make a power supply that could do both - or neither. But it likely comes down to price for the manufacturer of the tv

Right, but I think it wasn't a real intended use case and that some TVs provided amperage over the spec (maybe by accident? simpler circuit bridging the same power pin for USB and HDMI?).

I had the same first gen Chromecast (may even have it lying around somewhere) but it came with explicit directions to use the included power cable, so maybe they updated the included guide some time after release.

They probably just provide extra power over the port. It costs extra to design an extra supply for a specific port so it’s probably shared, and likewise also costs extra to current limit each port. So more than likely a cost saving measure