Nintendo sells the Switch 2 dock as a chunky plastic brick that costs more than some games. A hobbyist just proved the whole “proprietary handshake” story holds up to about 540 bytes of code. That’s it. Five hundred and forty bytes, patched into a $45 Cable Matters USB-C hub, and the console happily believes it’s sitting in an official dock.
I love this kind of story. Not because it’s useful to the average player (it mostly isn’t, yet), but because it strips the marketing mystique off a product in one afternoon of poking around with a sniffer.
How the Switch 2 dock check actually works
The modder, who goes by mkopec, started from a frustrating but familiar situation: the hub charged the console fine and even negotiated DisplayPort Alt Mode, yet no picture ever came out. So he put a USB-PD sniffer between the real dock and the console and watched the conversation.
It turns out the dock advertises two vendor IDs, one for DisplayPort and one for Nintendo’s own mode. The console enters Nintendo’s mode first, sets up DisplayPort, then sends a handful of vendor-specific messages. Answer those the way the official dock does, report Nintendo’s vendor ID instead of VIA’s, offer 15 V at 2.8 A like the real thing, and TV mode lights up. Seven firmware revisions later, the hub even matches the full sequence closely enough to kill a three-second pause, as Tom’s Hardware reported.
Remember when accessory makers told the press the dock check used encryption and a dedicated chip? Copied identity data and fixed replies did the job here. Either those makers were guessing, or Nintendo’s “security” is doing far less than everyone assumed. It reminds me a lot of the ThinkPad BIOS password bypass from this week: the scary lock is often just a polite request.
The HDR bonus nobody asked for
Getting video out would already have been a nice weekend. But the picture was washed out with HDR on, so mkopec kept digging. The culprit was the hub’s Realtek RTD2142 chip signaling BT.709, the plain SDR color space, even when the console was pushing HDR. A 108-byte patch, flashed over I2C riding on the DisplayPort AUX channel through the same USB-C cable, fixes the flag to BT.2020.
Funny detail: one third-party dock’s firmware contains a debug string that literally reads “switch2 color space patch”. So the vendors know. They just don’t tell you.
Not everything works, mind you. VRR shows up in the console’s menu because the hub now claims to be the official dock, but enabling it freezes the DisplayPort output and HDMI stays stuck at 60 Hz. The USB ports and Ethernet weren’t tested seriously either.
Should you try this on your own USB-C hub?
Probably not, unless you enjoy fwupd, flashrom and the risk of bricking a perfectly good hub. The blog post explains the method but shares no code or patch files, and the modder admits he doesn’t understand many of Nintendo’s commands, so unknown messages just get the hub’s stock reply. That’s fine until the next system update changes the script. Firmware 21.0.0 already left some third-party docks charging with no picture, and those vendors at least shipped fixes. A hand-patched hub has nobody behind it.
Still, the economics are hard to ignore. Nintendo wants around 120 euros for a second dock. A compact hub costs a third of that, works with your laptop and phone, and fits in a jacket pocket. This is the same energy as running Steam games on a jailbroken PS5: the hardware is capable, the restriction is a business decision.
What I’d do? Wait. Now that the handshake is documented, cheap docks that answer it properly are inevitable, with or without Nintendo’s blessing. And if you mostly care about how your games actually run on a handheld, Valve just started publishing real Steam Deck FPS numbers on store pages, which is more transparency than Nintendo has ever offered about its dock.
Five hundred and forty bytes. That’s the price of admission to Nintendo’s walled garden.
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