§ Series · Ethernet multi-radio · Zigbee + Thread

SLZB-MRxU.
One body. Five radio brains.

Name: SLZB-MRxU Series
Brand: SMLIGHT

Pre-flashed, PoE-powered, open-firmware-friendly Ethernet coordinator. Pick the SoC pairing that matches your network — everything else is identical.

Current model

SLZB-MR1U

Radios

CC2652P7 + EFR32MG21

Availability

In stock — ships in 48h

Where to buy Compare all five →

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160 × 24 × 28 mm · 86 gENGINEERED · UKRAINE

§ SELECT MODELEverything identical except the two radio SoCs

§ 01 / Why MRxU

Five variants. One hardware philosophy.

Same body.
Same ports. Same firmware.

Ethernet-first by design

Wire it into your rack, your panel, your basement — anywhere the mesh needs to live. Wi-Fi is available as a fallback; Ethernet is the default because it's the right answer.

Two radios, running at once

Zigbee on one SoC, Thread on the other — simultaneously, on separate channels. No more mutually-exclusive network stacks.

PoE, USB-C, or both

One Cat6 drop delivers data and power. USB-C works too — and the two sources can coexist thanks to optoelectronic isolation.

§ 02 / Chipsets

The only thing that changes between variants.

Radio SoC pairings.
Pick by network, not by body.

RADIO 1

CC2652P7

Texas Instruments

Zigbee / Thread

ANTENNA 1 · +5 dB · rotatable

RADIO 2

EFR32MG21

Silicon Labs

Zigbee / Thread

ANTENNA 2 · +5 dB · rotatable

Radio SoC

Vendor

Capabilities

Year

Current pick?

CC2652P7

Zigbee 3.0 · Thread 1.3 · +20 dBm

2023

● IN MR1U

CC2652P

Zigbee 3.0 · Thread · +5 dBm

2020

—

CC2674P10

Zigbee 3.0 · Thread 1.3 · +20 dBm · extended RAM

2024

—

EFR32MG21

Silicon Labs

Zigbee 3.0 · Thread · +20 dBm

2019

● IN MR1U

EFR32MG24

Silicon Labs

Zigbee 3.0 · Thread 1.3 · AI/ML accelerator

2022

—

EFR32MG26

Silicon Labs

Zigbee 3.0 · Thread 1.4 · 2× RAM vs MG24

2025

—

Shared across every variant

ESP32-S3

Core · 2× 240 MHz

Runs SLZB-OS. Orchestrates the two radios, USB passthrough, the web UI, OTA updates.

W5500

Ethernet · WIZnet

Hardwired 10/100 Mb Ethernet SoC — the PHY that keeps the network link deterministic.

PoE Xfmr

SMLIGHT 5V

Isolated PoE transformer — 802.3af (48V). Delivers clean power while keeping USB-C-side circuitry separated.

§ 03 / Functions

What this thing actually does.

12 capabilities
organized by layer

CORE

Zigbee Adapter

Coordinator or Router. Native Zigbee2MQTT and ZHA.

CORE

Thread Adapter

Border router for Matter-over-Thread. Simultaneous Zigbee + Thread.

CORE

USB Passthrough

Plug any CP210x / CH340 dongle into the MRxU and expose it over the network.

I/O

LAN · Wi-Fi · USB · PoE

Network and power over whatever your rack allows. All four can be used.

FIRMWARE

Pre-flashed

Ships working. No toolchain, no flashing cable, no 3 AM.

FIRMWARE

ESPHome

Swap to ESPHome via the built-in flasher if SLZB-OS isn't your vibe.

FIRMWARE

SLZB-OS

WireGuard · DDNS · OTA · Zigbee Hub · OTBR · USB Passthrough.

FIRMWARE

Web-UI auth by default. Not an exposed service.

HARDWARE

2× Rotatable Antennas

L-I-shaped +5 dB. 3-axis movement for placement.

HARDWARE

6 LEDs + Button

Visual feedback on radios, PoE, link, activity. One physical button for mode control.

HARDWARE

DIY Pinouts

ESP32-S3, radio-SoC debug pinouts exposed. Bring your own probes.

HARDWARE

Tiny Design

160 × 24 × 28 mm. Sticks to a wall with a strip of 3M.

§ 04 / Firmware · SLZB-OS

Ships with SLZB-OS. Swap at any time.

Local-first.
Community-welcomed.

SLZB-OS

The official operating system running on the ESP32-S3 core. Ships pre-flashed and tested on every MRxU.

Web UI — setup, configuration, one-click firmware updates
Zigbee Coordinator, Router, Hub mode, and Matter-over-Thread border-router roles
Home Assistant integration — ZHA, Zigbee2MQTT, and SMLIGHT's native HA integration
PoE control, debug logging, hardware diagnostics
One-click reflash to ESPHome, community firmware, or back to SLZB-OS

ESPHome

For DIY. Basic radio adapter functionality — YAML-configurable.

Tasmota · Community

Flash your own ESP32-S3 firmware via the built-in web flasher.

Open-source core

SMLIGHT also publishes an open-source core FW — lighter than SLZB-OS, MIT-licensed.

§ 05 / Updates & Recovery

Never requires a flashing cable.

Everything OTA.
Everything recoverable.

Remote radio update

Flash both radio SoCs — the TI chip and the Silabs chip — via the web UI. Zero physical access required.

Remote core update

SLZB-OS itself updates over-the-air. Click to deploy.

Reset function

Factory reset through the physical button. Recovers from any bad firmware flash.

DIY pinouts

Full debug pinout for ESP32-S3, CC265x and EFR32. Solder a header and connect your own probe.

§ 06 / Topology

Put it anywhere. Run it from anywhere.

Ethernet means location-free.
VPN means globe-free.

Run the Zigbee or Matter-over-Thread mesh in one building — House B — and reach it from your Home Assistant server across the city, the country, or the planet. Ethernet means the MRxU goes wherever the wire reaches; WireGuard in SLZB-OS means that wire can come back out anywhere.

§ 07 / Compare

Five variants. Side by side.

Click a column
to switch variant

Radio 1

CC2652P7

CC2652P

CC2674P10

EFR32MG24

Radio 1 vendor

Texas Instruments

Silicon Labs

Radio 2

EFR32MG21

EFR32MG24

EFR32MG26

EFR32MG24

Radio 2 vendor

Silicon Labs

Positioning

MAINSTREAM

VALUE

RECOMMENDED

PREMIUM

HOMOGENEOUS

Availability

In stock — ships in 48h

In stock

Pre-order — ships Apr 2026

In stock

Everything else

ESP32-S3 core · W5500 Ethernet · PoE 802.3af · USB-C · USB-A passthrough · 2× rotatable +5 dB antennas · 6 LEDs · button · 160×24×28 mm · 86 g · SLZB-OS

Not sure which to pick?

You want the mainstream pick

You want the essentials

You want the latest TI + Silabs chips

You want the most RAM / room to grow

You're standardizing on Silicon Labs

§ 08 / Electrical diagram

How the MR1U is wired.

Schematic-level.
Block diagram.

§ 09 / In the box

What you actually unbox.

180 × 25 × 40 mm
105 g packed

SLZB-MR1U device

160 × 24 × 28 mm · 86 g

Zigbee antenna

L-I · +5 dB · rotatable

Thread antenna

L-I · +5 dB · rotatable

Mount kit

2× screws · 2× adhesive pads

Hex wrench

Antenna tightening · 3 mm

QR-code manual card

Scan for the complete online manual.

§ 10 / Full specifications

Every number. Every port.

Same body.
Radios change per variant.

Radio 1 SoC

CC2652P7 (Texas Instruments)

Radio 2 SoC

EFR32MG21 (Silicon Labs)

Protocols

Zigbee 3.0 · Thread 1.3 · Matter-over-Thread

Simultaneous operation

Yes — both radios concurrently, separate channels

Tx power

+20 dBm (both radios)

Antennas

2× external, rotatable, L-I shape, +5 dBi

§ 12 / FAQ

11 questions. Straight answers.

Condensed from
community forums

MR1U. It's the mainstream pick — CC2652P7 paired with EFR32MG21 — and has the most community guides, tested firmwares, and Home Assistant coverage.

§ 13 / Video reviews

Independent reviewers. Actual installs.

12 videos
Page 1/4 · auto-rotate

14:22

SLZB-MR1U Review — the new mainstream Zigbee coordinator

Digiblur·38k subs

89k views·Mar 2026

22:08

I replaced 3 Zigbee dongles with one SLZB-MR3U — here's what happened

SmartHomeScene·72k subs

156k views·Feb 2026

31:47

Multi-radio deep dive: MR1U vs MR3U vs MR5U side-by-side

ModernHouse·24k subs

62k views·Apr 2026

Refreshes every 8s · See all on YouTube →

§ 14 / Owner feedback

12 owners. In their own words.

Rotating
every 9s

🇺🇸MR1U★★★★★

Swapped from a CC2652P dongle to the MR1U for the Ethernet + PoE combo. Put it in the basement wiring closet where my mesh was weakest — and suddenly the whole top floor came alive again.

u/basement_rack_robr/homeassistant·Apr 2026

🇺🇸MR3U★★★★★

Running MR3U as a dedicated Matter-over-Thread border router alongside my existing Zigbee coordinator. The dual-radio split lets me keep both networks on their optimal channels. Setup took 10 minutes.

matter_mesh_miker/MatterProtocol·Mar 2026

🇩🇪MR5U★★★★★

MR5U with twin MG24s is a dream for my standardization — one toolchain, one set of firmware builds, one debugging workflow. Silicon Labs only. Beautiful.

@embedded_ericSMLIGHT #developers·Feb 2026

12 quotes · Submit yours →

§ 15 / Useful links