TL;DR
- Doom has been successfully run on Apple’s Lightning to HDMI adapter.
- The dongle contains surprising computing power, including an SoC and RAM. This feat was achieved using iOS exploits and externally loading firmware onto the dongle.
“Can it run Doom?” has evolved to become a cult meme at this point, with developers and enthusiasts trying to run Doom on just about anything these days, including Android 16’s Linux Terminal. As long as something has some processing power, there’s bound to be someone hacking together a way to run the 1993 first-person shooter video game. There’s even a dedicated “It runs Doom” subreddit for this! The latest piece of tech that has been hacked to run Doom is Apple’s Lightning to HDMI adapter, and I’m surprised by how powerful this simple dongle is.
In the video above, Doom is running on the official Lightning Digital AV adapter, which Apple sells for a cool $49. You can get cheap alternatives on Amazon for as low as $10, but there’s a reason Apple’s dongle is so expensive. In addition to the Apple tax (the markup that Apple adds to its products), the company has also equipped this dongle with some surprising computing power.
As the developer pointed out in the past, Apple’s Lightning video adapters are essentially computers that feature Apple Secure Boot and run Darwin kernel. They come with an SoC (S5L8747) with 256MB of RAM, allowing them to output 1080p video. The adapter doesn’t have storage for the firmware, so the connected iPhone has to upload it to the adapter every time it connects.
If we are allowed to oversimplify this, the adapters run what can be equated to a super stripped-down version of iOS. As Reddit user soramac points out, the Mac in the above video is loading firmware onto the dongle since it has no persistent storage. Using some previously found iOS exploits, the developer managed to run the code for Doom on it.
The reason Apple has added so much overkill computing power to a simple dongle is said to be that older iPhones with Lightning only supported USB 2.0, which did not allow for HDMI output. The dongle is said to be receiving a compressed video stream from the phone over the USB 2.0 connection, decoding it on the fly, and creating the requisite HDMI signal for output. That’s impressive for a cable, to be honest.
This isn’t the first time an Apple accessory has turned out to be justified overkill. We’ve previously seen scans of Apple’s $129 Thunderbolt cable, showcasing an incredibly complex cable and connectors with their own complex PCB assemblies. Apple’s $9 3.5mm headphone jack adapter even packs its own DAC! So, while Apple charges a lot for some of its products for the use-case, sometimes the cost matches the functionality offered.
