Hello,
I bought the recommended USB dongle.
At Domadoo: SONOFF - USB Zigbee 3.0 Dongle + External Antenna (V2) ZBDONGLE-E compatible with Home Assistant and Zigbee2mqtt
I can see the USB port where it is located
moi@mamachine:~$ lsusb -d 10c4:ea60 -v
Bus 005 Device 006: ID 10c4:ea60 Silicon Labs CP210x UART Bridge
Couldn't open device, some information will be missing
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 [unknown]
bDeviceSubClass 0 [unknown]
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x10c4 Silicon Labs
idProduct 0xea60 CP210x UART Bridge
bcdDevice 1.00
iManufacturer 1 Itead
iProduct 2 Sonoff Zigbee 3.0 USB Dongle Plus V2
iSerial 3 d482b7865e32f111aa0bec30984367d3
bNumConfigurations 1
The installation goes well at least at the beginning then boom!
Apparently everything is « started »
But there is this message:
Zigbee2MQTT container error: h[2026-10-01 19:01:02] error: z2m: Error: Error: I/O error setting custom baud rate of 115200
Is this a speed (baud rate) issue?
Of course I restarted the server hosting Gladys several times.
Thanks in advance…
Hello. You need to choose the ZBdongle-E dongle (you chose the P in the list).
In Configuration > Dongle
Thanks for the suggestion.
The error message is no longer the same.
Zigbee2MQTT container error: G[2026-10-01 20:39:32] error: z2m: Error: Failure to connect
Strangely, the proposed devices are changing…
We’re making progress 
Can you tell us more about your setup (mini PC? Ubuntu?)?
“Failure to connect” means that Zigbee2MQTT cannot communicate with the key. The fact that the list of offered devices changes is a good indication: the key disconnects and then reconnects, and its path (/dev/ttyUSB0, /dev/ttyUSB1…) changes.
On Ubuntu/Debian, the most common cause is brltty (the service for Braille displays). It “captures” the CP210x chips (10c4:ea60, exactly yours) and disconnects the key in a loop.
Can you run these commands and send us the result (if you’re comfortable, no risk, these are read-only commands)?
ls -l /dev/serial/by-id/
sudo dmesg | grep -i -E "cp210|ttyUSB|brltty"
If you see brltty in dmesg (for example “interface 0 claimed by cp210x while ‹ brltty › sets config”), remove it and then restart your machine:
sudo apt remove brltty
After that:
- Unplug and then plug the key back in, preferably directly on the PC (without a USB hub) and with the USB extension cable if you have one.
- In Gladys, in Configuration > Dongle, choose the correct port again (the one that corresponds to the Sonoff key) and the ZBDongle-E model, then save.
My setup is as follows:
Geekcom mini PC with AMD processor, 32GB RAM, 2x 1TB SSDs.
On the first SSD, I have the following partitions:
- Root 60GB in ext4
- Swap 64GB
- /home 802GB in ext4
On the second SSD:
The main OS is Ubuntu Server 26.04.1 LTS
Then there’s Docker and its containers.
For the commands suggested, here’s what I get:
moi@mamachine:~$ ls -l /dev/serial/by-id/
total 0
lrwxrwxrwx 1 root root 13 Oct 1 18:23 usb-Itead_Sonoff_Zigbee_3.0_USB_Dongle_Plus_V2_d482b7865e32f111aa0bec30984367d3-if00-port0 -> ../../ttyUSB0
moi@mamachine:~$ sudo dmesg | grep -i -E "cp210|ttyUSB|brltty"
[ 3.523023] usbcore: registered new interface driver cp210x
[ 3.523054] usbserial: USB Serial support registered for cp210x
[ 3.523106] cp210x 5-2.1:1.0: cp210x converter detected
[ 3.563875] usb 5-2.1: cp210x converter now attached to ttyUSB0
moi@mamachine~$ sudo apt remove brltty
The package « brltty » is not installed, so it is not removed
I note that I need to back up my /var partition with rsync to allow rollbacks without reinstalling everything. Before each new integration or important step, an image of /var.
There’s Timeshift which could do this. So to simplify usage, I could replace my Ubuntu Server with Mint, which I know and use well.
It works!
Inspired by
ls -l /dev/serial/by-id/
total 0
lrwxrwxrwx 1 root root 13 Oct 1 18:23 usb-Itead_Sonoff_Zigbee_3.0_USB_Dongle_Plus_V2_d482b7865e32f111aa0bec30984367d3-if00-port0 -> ../../ttyUSB0
I changed the USB port to choose USB0.
It was the lsusb command that misled me:
It indicates Bus 005 Device 004: ID 10c4:ea60 Silicon Labs CP210x UART Bridge
So I went with USB4…
Sorry, but thank you anyway.
No problem. Glad it works 
For backups, don’t hesitate to check out Gladys Plus (which includes backups)
Gladys plus is for later, when my migration to Gladys is complete.
I’m not really looking for backups but the possibility to perform a system « rollback » in case of a botched installation.
