Yes, /dev/ttyUSB0 is definitely there and in addition dmesg | grep ttyUSB0 shows ‘usb 1-1.3: cp210x converter now attached to ttyUSB0’. Since the error message says Operation not permitted I was also thinking of a privileges issue (although I had never bothered with this in the initial setup) and I tried a sudo chmod 777 /dev/ttyUSB0 but also without any success, the same error remains showing.
Hey there 
I’ve had the same issues as you since I upgrade my linux Debian to the latest version.
Only way I found was to refresh the snap using --devmode flag.
Then it works.
The reason why ? Absolutely no clue … still, it works now … give it a shot
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Thanks for your suggestion!
However in my case when I try snap refresh zwave-js-ui --devmode I just get ‘snap “zwave-js-ui” has no updates available’ and nothing changes…
I have the latest/stable zwave-js-ui v8.18.1 Rev195 for the moment.
In the meantime I have also tried with a backup of my system of 30May on which I still have zwave-js-ui v8.16.2 Rev183 installed. This Z-Wave JS UI still works as before without any issues!
So by blocking future zwave-js-ui snap updates (with snap refresh zwave-js-ui --hold) of this older version I have a workaround to keep my Z-Wave JS UI functioning properly
Okay now I can’t follow anymore… I had swapped to my ‘newer’ system again to try out the suggestion above with the --devmode flag that didn’t work.
And when I just put my 30May SD card in again with the older zwave-js-ui v8.16.2 Rev183 that worked just fine one hour ago, now I get the same error message showing Driver: Failed to open the serial port: Error: Operation not permitted, cannot open /dev/ttyUSB0 (ZW0100)
Error: Driver: Failed to open the serial port: Error: Operation not permitted, cannot open /dev/ttyUSB0 (ZW0100)
???
So I was wrong, it is the zwave-js-ui ‘working’ Rev44 => ‘problematic’ Rev189 update on 4Jun that caused the issue on my primary system. And when I started up my backup system, there was an immediate update from the initially ‘working’ Rev177 => also ‘problematic’ Rev183.
So before I could apply the snap refresh zwave-js-ui --hold there was already a new snap update that destroyed my workaround for this issue 
YES now I got there thanks to your tip!!! 
But to obtain a real update (unlike my previous try when I already had the latest revision installed) I now did snap revert zwave-js-ui --revision 189 at first.
After that snap refresh zwave-js-ui --devmode does a real upgrade to the latest zwave-js-ui v8.18.1 Rev195 again and thanks to the --devmode flag everything seems to work fine again!?
So reading about the usage of this --devmode flag Put snap in development mode and disable security confinement => my problem had something to do with the ‘security confinement’ of the snap…?
I guess @joachimmg can explain and help to prevent these kind of issues in the future
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Hi,
This is an issue with Debian and not this snap package. You can read more about it in the snap channel of the Zwave-js Discord.
There’s also these:
Hi Team, apologies if this is a newbie mistake but I am having difficulty with device states updating.
I am running an Aetoec Zwave Stick 5 and aeotec switches and dimmers all of which I know should be capable of polling as other half has them running in HA with no issues.
Using Zwave JS UI and noticed that if I change device state in JS UI it doesn’t show in HA and also, more importantly, when I use physical switch HA isn’t updating. Does anyone have any suggestions as assume I have done something wrong. Have tried both Zwave JS and JS UI and having the same issue.
I had once same isse with one of my switches. Re-interviewing the device solved my problem.
So I know this is not the right place for this, but may be someone can push me in the right direction. I see binary switch and I get that, but how do I use scene activation? Once I can trigger the scene from my light switch, how can I use it in an automation?
I’ve been searching and looking but haven’t seen anything in the documentation for zwave_js_ui. I’m pretty sure I don’t know what to look for. I tried searching for scene activation v1 or scene actuator configuration v1 but with no luck. I have a zwave button that only has scene activation and scene actuator because it is not physically connected to a switch.
I also made a thread about it and got no response so far. Maybe I need a different title…
You use the scene actuator configuration settings to assign a dimming value to each scene. This is like making presets that get stored in the device. Then when you type in the scene number in SCENE ID box under SCENE ACTIVATION the device will activate the settings associated with that scene.
do you mind if I message you in your inbox? I don’t want to hijack the thread any further.
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First of all, thank you for the great guide. However, I am still stuck… I followed the guide and started fresh with a Raspberry Pi 4 + an old Zooz Z-Wave stick (ZST10).
I got up to step 4 where “sudo snap interface serial-port”
For this, I am only shown:
name: serial-port
summary: allows accessing a specific serial port
plugs:
- zwave-js-ui
I don’t know how to execute the next step "sudo snap connect zwave-js-ui:serial-port " and I think that is causing me problem in the UI and following steps.
The stick is powered, in UI I can see it being /dev/ttyACM0. When I unplug it, /dev/ttyACM0 is gone from UI Settings.
I also tried setting the UI settings Serial Port to /dev/ttyACM0 but still have error at the top:
Driver: Failed to open the serial port: Error: Operation not permitted, cannot open /dev/ttyAMA0 (ZW0100)
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I think there were others having same issue as you. Check the replies above, whether it helps.
Same problem over here!
I manage to get Zwave-JS-UI working on a freshly installed RPI (Debian Bullseye from 2023-05-03) in the way perfectly explained above,
but as soon as I update Bullseye (“sudo apt update” && “sudo apt upgrade”) Zwave-JS-UI can no longer connect to my Zwave stick (“Driver: Failed to open the serial port” in Zwave-JS-UI and “sudo snap interface serial-port” no longer shows a “core”…).
very frustrating…
I am going to try to re-do the procedures without upgrading the debian to the latest and the greatest…
Edit:
I started fresh without first updating the OS. It looks like it works now. I believe it is what the above posts said one of the updates broke the settings and I don’t know how to fix it…
The solution is to, in the beginning of step 3
instead of sudo snap install --channel=stable zwave-js-ui
use sudo snap install --devmode --channel=stable zwave-js-ui
based on the earlier hint of @TheMadDotNetDev.
So then you’re in --devmode from the start and that works (for me). You can also hold the updates for a while and later when an update is available do a refresh with --devmode (like @TheMadDotNetDev originally suggested)
I updated Home Assistant Core to 2023.10 and it now says I need a newer version of Z-Wave JS UI.
I checked snap list and I’m running latest/stable which is v8.26.0 (zwave-js-ui: 8.26.0.08e6a7e, zwave-js: 11.14.3).
I am going to temporarily roll-back my home assistant image to an earlier backup, but what’s the solution here?
Unfortunately the snapd store didn’t upgrade the version as fast as Home Assistant required. I think if you want to use 2023.10, you have to then switch to latest/candidate, it is now at v9.0.3.
Ah okay thanks.
Is there a timeline for snap stable to update? I don’t mind holding HA core back for awhile.
Just build zwavejs-ui with NodeJS and Yarn instead. It’s super easy and takes only a few minutes.
It’s described here, the last method at the very bottom of that page. That’s how I always build zwavejs-ui.