SLZB-MR1U Performance Updates
29-Aug-2025
❤️ Firmware 3.0.0 Released for SLZB-MR1U – USB Passthrough + EFR32 OTA updates Now Fully Restored!
We’re excited to announce the release of SLZB-OS v3.0.0 for the SLZB-MR1U, which includes major improvements and long-awaited fixes:
✅ What's New in v3.0.0:
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USB Passthrough fully restored and stabilized
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EFR32 OTA firmware update issue resolved - flashing now works reliably
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General performance improvements and internal optimizations
➡️ How to Update:
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OTA Update: If available, simply apply the OTA update for SLZB-OS from the device’s web interface
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Manual Update via Type-C (one-off): Use our web flasher here: https://smlight.tech/flasher/#SLZB-06U-MRxU
⏬ Coming Soon: Multi-Device USB Support
We’re now working on enabling support for multiple USB devices connected at the same time (e.g., Z-Wave + 4G/LTE modem, for example, via USB). This will open the door to even more modular and flexible smart home setups.
Stay tuned for updates — and thank you for your continued feedback and support!
26-Aug-2025
⚠️ Release 2.9.9 - Important Notice: USB Passthrough Temporarily Disabled
We would like to inform all users of the SLZB-MR1U that, following extensive "field feedback" by the first Customers, a stability issue has been identified when USB passthrough is enabled. Specifically, the feature caused interference with onboard serial ports, affecting the operation of radio modules - CC2652P7 and EFR32MG21.
❌ Issue Summary
When USB passthrough was active, the device occasionally experienced:
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Instability in radio communication, in particular, flashing the EFR32MG21 SoC (Thread) would fail after the second or third attempt, rendering firmware updates unreliable.
These issues were directly linked to USB passthrough affecting internal UART routing and resource handling.
✅ Action Taken
To ensure stable performance of the SLZB-MR1U in its primary function as a LAN-based Zigbee/Thread coordinator, the USB passthrough functionality has been temporarily disabled in the latest firmware version.
As a result:
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Radio functionality is now fully stable
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EFR32 firmware flashing now works reliably
➡️ Next Steps
We are actively working on a more robust USB passthrough implementation that will allow safe use of external USB devices (e.g., Z-Wave dongles) without compromising internal radio operations. This will require architectural changes and may take time to complete.
We will provide updates as development progresses.
➡️ Latest Firmware
The latest stable firmware (with USB passthrough disabled) is available here:
⏬ [Download Firmware]
To update your SLZB-MR1U:
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Download the firmware file.
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Open the device’s web interface (http://slzb-mr1u.local, if mdns is enabled in your local network)
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Navigate to Settings and Tools -> Firmware Update tab.
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Click on Flash the custom firmware (section under SLZB-OS Update (OTA)) and upload the file, and wait for the process to complete.
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Reboot the device after flashing.
❓ Questions or Support
If you have any questions, use cases, or require support, feel free to contact our support team via the ticketing system.
We appreciate your patience and continued trust as we work toward a complete and stable solution. If you are not happy, we can get the device back and refund.