There are certain pitfalls to being an early adopter, and lest anyone needed reminding of that, it has been confirmed that the first run of Raspberry Pi 4 boards have a USB-C charging issue.
Following the launch of the Raspberry Pi 4 a couple of weeks ago, reports surfaced that it was not playing nice with some USB-C cables. Specifically, some USB-C cables were not delivering power to the mini PC.
One of the co-founders of the Raspberry Pi Foundation, Eben Upton, confirmed the issue to TechRepublic. He said that smart chargers with an e-marked cable—ones that have a special chip inside to automatically adjust current—incorrectly recognize the Raspberry Pi 4 as an audio accessory "and refuse to provide power" to the mini PC. These cables are commonly found bundled with MacBooks and laptops that have USB-C Thunderbolt charging ports.
While nothing is set in stone yet, it does not appear as though this is something that will be addressed with a firmware upgrade, unfortunately.
"I expect this will be fixed in a future board revision, but for now users will need to apply one of the suggested workarounds. It's surprising this didn't show up in our (quite extensive) field testing program," Upton said.
The issue was brought to light in a blog post by Tyler Ward. What it boils down to is Raspberry Pi muffed the development of its own circuit design. A proper USB-C port is supposed separate 5.1K ohms resistors for each of the two "CC" pins. Raspberry Pi's non-compliant design has them sharing a single resistor, which causes problems with some USB-C chargers and cables.
The good news is the USB-C port otherwise seems to work. While the issue is annoying, it's at least not catastrophic. Current Raspberry Pi 4 owners can sidestep the issue by using a non e-marked USB-C cable, or buying Raspberry Pi's own $8 power supply.
If you were planning to buy a Raspberry Pi 4 board, it might be worth waiting for a future revision. Raspberry Pi told ArsTechnica that a new revision will be out in the "next few months," and that it will have a spec-compliant USB-C charging port.