Sticky Request Mods can I please ask this be made a sticky? I feel this is important information and should be easily accessible Sticky Request
In my journey of getting a good working Home Assistant setup I have hit some walls along the way and I’m going to discuss 1 of those now in the hopes this information is useful to someone.
If you are in the UK and need help with the hardware modification outlined below please contact me as I am considering a modification service for this
The problem:
The Aeotec Z-Stick Gen5 is a well known and loved Z-Wave stick but unfortunately for some of us we have found that this stick no longer works on a Pi4. The reason for this is hardware. Technically the D+ is pulled up to 5V when plugged in and the Pi4 cannot handle this and rejects the stick. One method of fixing is to use a USB hub but this isn’t ideal and certainly not a good enough fix for me so please read on…
Can it be fixed? YES! Skip this technical section if you just want the fix below
So lets get technical!
The Aeotec Z-Stick Gen5 is a confusing one, from my research and speaking to Aeotec directly there are actually 4 versions of this stick, YES 4! And they all get called exactly the same thing and look exactly the same!
So what are the differences and how do I tell which stick I have?
This isn’t easy either lol
The initial release of this stick runs Z-Wave library 3.95, SDK version V6.51.02 and firmware version V1.00 - Some of these units can be updated to the newer V1.01 firmware but not all of them. These sticks don’t work on a Pi4
The second one has a Z-Wave library of 4.54, SDK version V6.51.10 and firmware V1.01. These sticks don’t work on a Pi4
The third (typically called the “New Z-Stick Gen5”) also has a Z-Wave library of 4.54, SDK version V6.51.10 and firmware V1.01. These sticks DO WORK on a Pi4 - These already have the hardware modification I will explain below
The Fourth (typically called the “Z-Stick Gen5+”) has a newer Z-Wave library (not sure of the version if anyone can help?), SDK version V6.81.06 and firmware V1.02. Uses a newer 500 series chipset (supports “SmartStart” and prob more, S2?). These sticks DO WORK on a Pi4 - These are current not available as far as I am aware - at the time of writing Aeotec said these should be available from them directly on popp.to in about a month or so.
So now you know the difference how can you tell which one you have?
Well not easily…
Plug it into your Pi4, does the Pi4 see it straight away? If yes then you have the third revision as listed about. If it doesn’t then you have one of the first revisions. To find out which you need the “Z-Wave PC Controller 5” software, also known as “Zensys Tools”. This is available to download here: https://www.silabs.com/products/development-tools/software/z-wave
Scroll down to “PC Programmer” to download, you must register first to download.
New Link Download
Once installed plug in your Z-Stick then open the software. Click on “Network Management” and you will see the device firmware version similar to this picture which will tell you if you have the first or second revision as listed above:
Now all that’s out the way, how do we fix it??
Well its quite simple actually but its a delicate process. The process involves desoldering a tiny SMD resistor on the circuit board and rerouting it. What this does is stops the D+ being pulled up to 5v and instead pulls it up to 3.3v allowing the Pi4 to connect to it properly straight away. The resistor in particular is R33 (R33 is 1.5k Ω, SMD package size 0402, power 1/16W). So in 3 pictures this is how it’s done:
*As a note I can’t see it being a problem to solder the resistor directly to the VCC and solder the wire from the resistor on the VCC to the bottom solder pad of the original R33 location as this way you could keep the resistor flat and it should look a little “tidier” although I haven’t tried this yet I plan to and will update this post accordingly.
I hope this thread has been helpful and answers some questions for those thinking about this stick and a Pi4. I for one didn’t realise that this stick isn’t actually available with the 500 series chip in it yet! Only the 300 series, and as for the newer Z-Stick 7, although its rumoured to be available soon even if it does come out its very unlikely to be supported for a very very very long time. To quote Aeotec “unfortunately we’ve encountered an issue where Series 700 uses a different API (bridge z-wave library) which pretty much none of the softwares available support it. It is being considered to be released as an experimental device to help push development and testing for OZW community”
which for similar price offered better features (although I know S2 isn’t supported in HA but might be a good way to future proof myself) so I ordered the Gen5+ as well even though it had no reviews.
) … which seemed odd because the physical stick on the back shows 908.42Mhz frequency which is US Z-Wave and also I was able to add my Z-Wave device successfully. I then started to wonder if perhaps this is a fake replica of Z-Stick given that Aeotec had no reference to this Gen5+ model on their site, and both the Gen5 and Gen5+ had the same model name ZW090-A and FCC Id printed on them, and I know Amazon is known to sell fake items from time to time. I then started to dig more into this and identified that the Gen5+ was at least running a newer device firmware, v6.07 suggesting it is a newer version at least. That led me to this forum thread that helped me confirm this Gen5+ is indeed a new model 
