Defeating LiftMaster Security+ 2.0: The $12 "Trojan Horse" Button Hack

I hate cloud dependencies. I especially hate when companies like Chamberlain (LiftMaster) lock down their hardware with "Security+ 2.0" encryption to force you into their MyQ cloud ecosystem.

If you have a yellow learn button on your opener, you know the pain. You can't just use a simple relay to short the terminals anymore. The motor expects an encrypted signal. If it doesn't get it, it ignores you.

People are buying expensive adapters or flashing custom ESP boards to get around this. I went a different route. I realized I didn't need to crack the encryption. I just needed to trick the device that already speaks it.

The Trojan Horse: LiftMaster 883LMW

The opener trusts its own wall buttons. So I bought the cheapest one they make: the LiftMaster 883LMW. It's a simple doorbell-style button that costs about $12.

Since this button is officially supported, it handles all the rolling code encryption natively. My plan was simple: use a smart relay to "press" this dumb button.

The Hardware

• LiftMaster 883LMW: The sacrificial button.
• Zooz ZEN17 800LR: This is the brain. It's a Z-Wave relay with two inputs and two outputs. It's rock solid and doesn't clutter my Wi-Fi.
• Spare Ethernet Cable: I stripped this to use the individual twisted pairs for my low-voltage runs.
• Soldering Iron & 14ga Wire: To make the physical connection.

The Hack

1. I cracked open the 883LMW casing to expose the PCB. It's a very simple board. I located the two solder points for the actual tactile button.
2. I took two strands of wire and soldered them directly to the legs of the push button.

Effectively, I created a parallel switch. If I touch these two wires together, the board thinks the button was pushed, and it sends the encrypted "Open" command to the garage motor.

The Wiring

I ran the wires from my modified 883LMW to the Relay 1 terminals on the Zooz ZEN17.

I mounted the ZEN17 centrally and used a single Ethernet cable to run signals to both my garage doors. Since Ethernet has 8 internal wires, it's perfect for this. I used one pair for the modified button and another pair for the magnetic contact sensors I mounted on the door rails.

Why This Wins

1. It's Cheap: The button was $12. I already had the ZEN17 handling my other door, so this cost almost nothing to add.
2. It's Local: The ZEN17 talks Z-Wave to Home Assistant. No Wi-Fi, no cloud, no API that Chamberlain can shut down next week.
3. It's Reliable: Because I'm using an official LiftMaster button to generate the signal, the motor never rejects the command.

Now, when I tap "Open" in Home Assistant, the ZEN17 closes the relay for one second, the 883LMW thinks a human pressed it, and the door opens.

Take that, Security+ 2.0.