[Guide] Nortek HUSBZB-1 NVM Backup/Restore and Updating Z-Wave Firmware

Note: If you want to just backup/restore/clone the stick, just use the ZStick G5 tool from the Sofware Prep Section

For flashing, if you have a non-us Hubitat that came with two separate sticks, this will not work for you. This is only for the Nortek combined Z-Wave/Zigbee stick.


Why you shouldn't do this:

  • Most people don't need to do this, and should not attempt this. No new features will be added to Hubitat unless they open up support to them in the older Z-Wave stack which they have said is end of life.

  • To flash the firmware you have to source a pin on the chip to ground with a free wire. If you touch a different part of the board you could short it out and destroy the chip.

  • Once you upgrade, you can't downgrade the chip to the previous firmware version as I haven't been able to source a firmware hex file from sdk version 6.51.06 and the chip has read protection enabled.

  • While the firmware is backwards compatible, and I haven't had any issues running it, Hubitat will not support any issues as a result of modifications done.

  • If you click on an erase button by accident in the programmer, you will lose your calibration data for the stick and render it useless, unless you took an internal NVM backup (this is different from external NVM backups from tools like the Z-Stick Gen5 tool or ZMESerialUpdater).

  • While unlikely, the hardware could fail while flashing rendering it useless.

Why Upgrade?

The Nortek stick runs a Z-Wave library version from SDK version 6.51.06 from 2014-2015. I couldn't find anyone that had attempted to upgrade the Z-Wave portion of this stick before, so I did some research into the datasheet for the SD3503 that powers the Z-Wave portion of the stick, and successfully found a way to upgrade it. After you upgrade you will be on version 6.82 which is the latest available. This opens up a number of features to the stick. Again, unless Hubitat adds support, these will be no good to you unless you run this on a different platform such as the Z-Wave official PC controller, or a project like OpenZwave.

  • Updated Z-Wave Library features

    • New Serial API features (tested)
      • Official NVM backup/restore functions
        • A side note: you can backup the stick already with tools like Z-Stick Gen5 Backup Tool, or the ZMESerialUpdater tool. I have successfully cloned a stick using this method. There is also a method to backup the zigbee portion with a different tool, which I'll probably make a guide for in the future. The api and format of the backup are different though vs using the official api method here.
      • Transaction report information on received frames
        • RSSI info, routes taken, latency
    • SmartStart (untested)
    • S2 encyption (untested)
  • Can flash different Z-Wave firmwares

    • Official Bridge/Static firmwares
      • The stick could be used with Z/IP gateway projects as that requires a bridge firmware, and series 700 chips only have bridge firmware available to them. This is/was the go forward for certified Z-Wave controllers, but I've heard rumors that the serial api could be certified for use with 700 series chips in the future.
    • Zniffer firmware.
      • Allows you to sniff z-wave packets
  • If Hubitat ever opens up manual radio backup/restores within the UI using the raw nvm files, the new serial api would potentially allow backups/restores to this stick. Bruce had mentioned that the stick was missing functionality that would allow this to work, and this appears to be it. Even if this is not the case, you could manage your own backups yourself using PC software.

  • Any NVM backups taken before the upgrade seem to restore just fine to the new version, so you can keep your network/node settings when upgrading.

Tools/Software Needed

Needed Software:
Z-Wave SDK - Contains controller firmware hex files
Z-Wave Programmer - Backup and flash new firmware
CP210x Driver - Windows Driver
Z-Stick Gen5 Backup Software - Used to backup external NVM

Optional Software:
PC Controller - Can be used for nvm backups and/or to verify new firmware version

Nortek Stick
Plastic Spudger/Guitar Pick
Stiff small guage wire to short reset pin
USB extension cable (Nice to have so you can work with the stick farther from the USB port)
Steady hands

Software Prep


  • Install the cp210x drivers

Backup up the external NVM (network and node info)

  • Download the Z-Stick Gen5 Backup software and run zwave_500.exe

    1. Select the com port for Z-Wave under the settings menu.
    2. Ignore all UI items except the "Read Eeprom" button.
    3. Click "Read Eeprom" and label and store the backup in a safe place. This contains your node and network information and can be used to restore/clone the stick.
  • If you ever need to restore you network/node settings you can restore this file using the "Write Eeprom" button

Download and Install Z-Wave Programmer.

Download the Z-Wave sdk, and put the new controller firmware file aside. Ensure the file matches below:

  • SDK_v6_82_01\SD3503\ProductPlus\Bin\SerialAPI_Controller_Static\serialapi_controller_static_OTW_SD3503_US_WITH_BOOTLOADER.hex

Download and install PC Controller if you want to verify that the library successfully updated or to use new features such as NVM backup/restore.

Hardware Prep

  1. Take the spudger or guitar pick and carefully separate the PCB from the plastic body.
    Plug the usb stick into the usb extender and take care to keep the stick from touching any metal components that could short it out.
  2. Orient the board with the Z-wave module pointing up ( the side with the smaller chips ).

3. Take one end of the metal wire and ground it to the metal usb plug taking care not to short out components on the board. I recommend doing this while the other end is unplugged. I pushed it in when the stick, so I didn't have to hold both ends.

Locate pin number 15 (RESET_N) below. Pin numbers go from 1-32 starting from the top left of the chip going counter clockwise. Pin 15 will be the 2nd from the right on the bottom of the chip.

Make sure your usb stick extension cable is not plugged in and practice grounding pin 15. Ensure that you can place the other end of the wire on that single pin. You will need to do this several times throughout the backup and programming process. You must take care to not let it contact other sections of the board as it could short out the chip.

Programming the chip

With everything set up open the Z-Wave programmer tool.

WARNING - When using this tool do NOT click the "Erase code space and lock bits" button. This will erase vital calibration data, than can't be restored unless you have a backup of the NVR section later in the guide. Even then, I don't have the steps to restore the calibration data if it is lost.

  1. Click on the ZW050x tab at the top.
  2. Click on Setting and select the Z-Wave com port
  3. Click Yes on the box if it asks you if you want to continue with UART programming.

Main Firmware backup:

  1. Click the "Read button" to try and backup your existing firmware. Note that the chip is most likely locked, so it will only return the CRC which could be useful if the original firmware is located, or if for some reason your chip isn't read protected. Please let me know if it isn't so we can have a way to restore the original firmware.

  2. This box will popup after

  1. Before clicking ok, ensure you are holding the wire down on Pin 15. It must be held down for the entire read process. It will take about a minute.

  2. Keep holding down the wire until this popup shows

  1. On the right side of the page, click the save icon and save the file as OriginalFlashCodeMemory.hex. If you notice that the contents don't have mostly zeros in the middle please let me know as your chip wasn't locked and you can read the original firmware.

SRAM backup:

I don't believe this is needed, but can be done for completeness.

  1. Click on the SRAM tab, and click the read button. Follow the prompts and ground the reset pin when needed. Save the file as Sram.hex by clicking the save icon on the right side.

External Non-Volatile Memory
The nvm cannot be backed up in this tool over UART. This backup was performed earlier in the software prep section.

NVR backup

This section is chip specific and needs to be backed up, and should only be restored to the chip it was taken from.

Click the "Read" button and follow the prompts to ground the reset pin when needed. Save the file as NVR.hex. You can also save a screenshot of the values that populate.

Lock Bits

Go back to the "Flash Code Memory" tab and click the "Get" button underneath "Lock Bits"

Take a screenshot of the returned data. If the "Read back protection" box is not checked after this, please share your OriginalFlashCodeMemory.hex file.

You can also click "Get Options", and save a screenshot, but it might not show valid values with read protection set.

Upgrading the firmware

On the Flash Code Memory section, click the 3 dots next to the "Hex File:" input, and open the file

If this is your first time flashing the newer firmware, also check the "Add S2 keypair" and "Generate S2 keypair"

Finally click the "Calibrate, Program, and Verify" buttons. Follow the prompts to hold down the reset pin the entire time it is flashing. If you don't, you will need to restart the process, as the flash will fail.

Verifying the firmware

Close the programmer out, and open Z-Wave PC Controller 5. Click on "Network Mangement" and select your controller node in the top left. On the right the new version should read "Z-Wave 6.09". An original stick will show 4.05.

Congrats! You now have an updated firmware. You can play around with the NVM backup/restore using this tool, as well as with SmartStart and including s2 devices as the controller will now show as S2 capable.


Thanks for this write-up. Amazing stuff, really.
I will probably try this out in the future, but since my hands are not so steady, while reading I was thinking if it would be possible to solder two wires (1 from pin15, other from ground) into a mini momentary switch I intend to procure at my local components store.

There does seem to be a plated-through hole (down slightly and to the right of pin 15) that is connected to the pin. Seems like you could solder to that pad if you first scraped the green solder mask from the pad/hole, thereby greatly reducing the chance of damaging the chip. Or, you could scrape the solder mask off the pad/hole and touch the wire there, reducing the chance of shorting an adjacent pin.


Thanks for pointing that out!

Thanks this worked perfectly. I have the C4 versiona and had to update this to update the LZW36 light and fan switch firmware

1 Like

I'm having some trouble tracking down the latest Z-Wave SDK that works with and contains the Z-Wave 500 Series firmware. Downloading SimplicityStudio v4 or v5 doesn't seem to offer up the right SDK either. Does anyone have any clue where I might find it? I did track down a link to version 6.81 straight from the Silicon Labs salesforce site, so they must still have direct links active... Just nothing listed on their website.

The PC Controller SW installed from Simplicity Studio 5 works with my Z-Stick which is 500 series.

What's the issue?

I'm having an issue finding the latest firmware update: serialapi_controller_static_OTW_SD3503_US_WITH_BOOTLOADER.hex

Ah you want updated firmware for your chipset - apologies misunderstood. I dunno where that is.. I've only used replacement firmware for zniffing otherwise the usb sticks, in my case Z-Stick+ (500 series) and UZB-7 (700 Series) just work.

I also cannot find the correct firmware file or the zwave programmer software. Simply studio 4 doesn’t allow you to find and download 6.81.

Can someone share those two downloads? Would be great to update the zwave side of my USB stick.

6.81 SDK:

Z-Wave Programmer:

1 Like

Thank you. I see it has the firmware, but older. Hopefully someone can share a download or a link to 6.82.02.

Found it:

> https://siliconlabs.force.com/s/validatezwsdk?ContentId=0681M000007yaWr%20&ContentType=ESDK&rURL=https%3A//www.silabs.com/products/development-tools/software/z-wave/embedded-sdk.html

Update: I followed the instructions and now have Z-Wave 6.09. Thank you for sharing. Always nice to squeeze all you can from existing hardware, even if it isn't 100% supported yet.

Many thanks! How the did you track that down? I looked for longer than I'd care to admit.

Used the way back machine.

I tried to find all the software but or I do not understand the instruction or I can not find them so instructions become useless... would anyone have all the windows packages needed ?
Many thanks for the instructions and your help

I successfully found all the software, followed the flash guide and validated that my flash was effective using PC Controller 5... But after performing this update, I no longer can pair (include) with any devices :worried:
Tried with ZwaveJS on a raspberry Pi first and then moved back to PC Controller 5, no matter what I do I can't get it to pair with anything. Sometimes after factory resetting one of my Z-wave peripherals (Innovelli lzw31-sn) I can get it to sucessfully exclude, but never include.

Even after putting in the switches DSKs I can't get them to smartStart, even though I see the controller now is responding to those packets.

So did I mess up my device somehow? Should I try re-flashing it again?
I have all the backups from the guide above, not sure if that can help.

Are you using the Nortek stick or something else? What firmware did you flash on it? Typically no firmware updates are required for use as a secondary controller as far as I know - it should just work.

Also from the screencap you have not included it with HE as a secondary controller so would not be able to pair any devices to HE that way anyway.

edit: I did try and use my old Nortek stick but that did not work with the PC Controller sw - maybe a usb driver issue or something dunno. I typically use either the UZB-7 or the Z-Stick+. The above screencap is a Z-Ztick+ paired as "device" on the HE with no security.

Yes, it is a HUSBZB-1 Nortek Secure & Control stick and I installed the firmware mentioned in the OP of this thread SDK_v6_82_01\SD3503\ProductPlus\Bin\SerialAPI_Controller_Static\serialapi_controller_static_OTW_SD3503_US_WITH_BOOTLOADER.hex

I'm sorry if I don't follow, this is my first Z-wave device and my introduction to Z-wave networking in general. I'm not sure if I follow when it comes to the term "secondary controller".
I'll try to read through more of the Silicon Labs documentation, but I'm still a little lost;
Either way I see you have Network Role: inclusion in your screenshot whereas mine only says Network Role: RealPrimary so I can tell something isn't correct with my setup.

It's good to know that you can't get the Nortek stick to pair using the PC controller either, but what other tool should I use to try and get it connected if it isn't working in Hubitat or Z-waveJS?

Download the Hubitat app