SLZB-06 Updated to 20260307 - Z2M couldn't connect anymore.

[Ruud-cb]

What happened?

Simply got home and it truns out everything was offline. SLZB-06 updated it's firmware automatically from 20250325 to 20260307. Core still on v3.0.8

I reverted the version back and everything worked again.

I know what you will be thinking: Outdated versions, firmware updates to the latest but Core doesn't. But respectfully I'm tired of trying to update to the latest versions and such. This combination has been running smoothly for 2 months and before that I had constant issues with BUFFER_FULL, TABLE_FULL, NO_NTWK_AWK or something like that errors. I don't want to run a home environment with constant technical issues. So I stick to the versions that work and have an update hell by the end of the year or something. So yea, sorry but I still thought it would be feasible to share, perhaps more people are going to update to the latest version automatically in a few days and run into similar issues.

How to reproduce it (minimal and precise)

I guess these combinations of versions gave errors?

Debug logs

  [2026-03-09 18:07:56] info:     z2m: Logging to console, file (filename: log.log), syslog                                                                                                             [2026-03-09 18:07:56] info:     z2m: Starting Zigbee2MQTT version 2.6.2 (commit #undefined)
  [2026-03-09 18:07:56] info:     z2m: Starting zigbee-herdsman (6.1.5)                                                                                                                                 [2026-03-09 18:07:56] info:     zh:zstack:znp: Opening TCP socket with 192.168.10.59:6638
  [2026-03-09 18:07:56] info:     zh:zstack:znp: Socket connected
  [2026-03-09 18:07:56] info:     zh:zstack:znp: Socket ready
  [2026-03-09 18:07:56] info:     zh:zstack:znp: Writing CC2530/CC2531 skip bootloader payload
  [2026-03-09 18:07:57] info:     zh:zstack:znp: Skip bootloader for CC2652/CC1352
  [2026-03-09 18:08:15] error:    z2m: Error while starting zigbee-herdsman
  [2026-03-09 18:08:15] error:    z2m: Failed to start zigbee-herdsman
  [2026-03-09 18:08:15] error:    z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions                                  
  [2026-03-09 18:08:15] error:    z2m: Exiting...                                                                                                                                                     
  [2026-03-09 18:08:15] error:    z2m: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)                                                                                
      at ZStackAdapter.start (/usr/lib/zigbee2mqtt/node_modules/.pnpm/zigbee-herdsman@6.1.5/node_modules/zigbee-herdsman/dist/adapter/z-stack/adapter/zStackAdapter.js:121:27)                        
      at Controller.start (/usr/lib/zigbee2mqtt/node_modules/.pnpm/zigbee-herdsman@6.1.5/node_modules/zigbee-herdsman/dist/controller/controller.js:127:29)                                           
      at Zigbee.start (/usr/lib/zigbee2mqtt/lib/zigbee.ts:67:27)                                                                                                                                      
      at Controller.start (/usr/lib/zigbee2mqtt/lib/controller.ts:101:13)                                                                                                                             
      at start (/usr/lib/zigbee2mqtt/index.js:79:5)  

The most interesting part is that it says Socked connected / ready and then still failed.

Details

os: #1 SMP PREEMPT_DYNAMIC PMX 6.8.12-17 (2025-11-21T11:16Z) - 6.8.12-17-pve - x64
node: v22.16.0
homeassistant: true
zigbee2mqtt: 2.6.2 (undefined)
zigbee-herdsman: 6.1.5
zigbee-herdsman-converters: 25.35.1
adapter: ZStack3x0 {"maintrel":1,"majorrel":2,"minorrel":7,"product":1,"revision":20250325,"transportrev":2}

[HansPeterDurand]

It look that i have a simliar issue: I got home and it turns out everything was offline. The configuration of the SLZ-06 as well a HA hasn't changed for months. I made an upgrade of the SLZB Dongle to SLZB-OS v3.2.5.dev1.
No luck. Here's an extract of Zigbee2MQTT log file:

[20:31:19] INFO: Preparing to start...
[20:31:19] INFO: Socat not enabled
[20:31:19] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.
[2026-03-09 20:31:39] error: z2m: Error while starting zigbee-herdsman
[2026-03-09 20:31:39] error: z2m: Failed to start zigbee-herdsman
[2026-03-09 20:31:39] error: z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2026-03-09 20:31:39] error: z2m: Exiting...
[2026-03-09 20:31:39] error: z2m: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
at ZStackAdapter.start (/app/node_modules/.pnpm/zigbee-herdsman@9.0.9/node_modules/zigbee-herdsman/src/adapter/z-stack/adapter/zStackAdapter.ts:107:27)
at Controller.start (/app/node_modules/.pnpm/zigbee-herdsman@9.0.9/node_modules/zigbee-herdsman/src/controller/controller.ts:145:29)
at Zigbee.start (/app/lib/zigbee.ts:70:27)
at Controller.start (/app/lib/controller.ts:111:29)
at start (/app/index.js:156:5)

[knucklebust0]

I have the same issues as well.
[20:14:37] INFO: Preparing to start...
[20:14:37] INFO: Socat not enabled
[20:14:37] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.
[2026-03-09 20:14:38] debug: z2m: Removing old log directory '/config/zigbee2mqtt/log/2026-03-09.20-06-02'
[2026-03-09 20:14:38] info: z2m: Logging to console, file (filename: log.log)
[2026-03-09 20:14:38] debug: z2m: Loaded state from file /config/zigbee2mqtt/state.json
[2026-03-09 20:14:38] info: z2m: Starting Zigbee2MQTT version 2.9.1 (commit #unknown)
[2026-03-09 20:14:38] info: z2m: Starting zigbee-herdsman (9.0.9)
[2026-03-09 20:14:38] debug: z2m: Using zigbee-herdsman with settings: '"{"network":{"panID":9294,"extendedPanID":[221,221,221,221,221,221,221,221],"channelList":[25],"networkKey":"HIDDEN"},"databasePath":"/config/zigbee2mqtt/database.db","databaseBackupPath":"/config/zigbee2mqtt/database.db.backup","backupPath":"/config/zigbee2mqtt/coordinator_backup.json","serialPort":{"baudRate":115200,"rtscts":false,"path":"tcp://192.168.50.2:6638","adapter":"zstack"},"adapter":{"disableLED":false,"transmitPower":20}}"'
[2026-03-09 20:14:38] debug: zh:controller: Starting with options '{"network":{"networkKeyDistribute":false,"networkKey":"HIDDEN","extendedPanID":[221,221,221,221,221,221,221,221],"panID":9294,"channelList":[25]},"serialPort":{"baudRate":115200,"rtscts":false,"path":"tcp://192.168.50.2:6638","adapter":"zstack"},"adapter":{"disableLED":false,"transmitPower":20},"databasePath":"/config/zigbee2mqtt/database.db","databaseBackupPath":"/config/zigbee2mqtt/database.db.backup","backupPath":"/config/zigbee2mqtt/coordinator_backup.json"}'
[2026-03-09 20:14:38] info: zh:zstack:znp: Opening TCP socket with 192.168.50.2:6638
[2026-03-09 20:14:38] info: zh:zstack:znp: Socket connected
[2026-03-09 20:14:38] info: zh:zstack:znp: Socket ready
[2026-03-09 20:14:38] info: zh:zstack:znp: Writing CC2530/CC2531 skip bootloader payload
[2026-03-09 20:14:38] debug: zh:zstack:unpi:writer: --> buffer [239]
[2026-03-09 20:14:39] info: zh:zstack:znp: Skip bootloader for CC2652/CC1352
[2026-03-09 20:14:39] debug: zh:zstack:znp: --> SREQ: SYS - ping - {"capabilities":1}
[2026-03-09 20:14:39] debug: zh:zstack:unpi:writer: --> frame [254,0,33,1,32]
[2026-03-09 20:14:45] debug: zh:zstack:znp: --> SREQ: SYS - ping - {"capabilities":1}
[2026-03-09 20:14:45] debug: zh:zstack:unpi:writer: --> frame [254,0,33,1,32]
[2026-03-09 20:14:51] debug: zh:zstack:znp: --> SREQ: SYS - ping - {"capabilities":1}
[2026-03-09 20:14:51] debug: zh:zstack:unpi:writer: --> frame [254,0,33,1,32]
[2026-03-09 20:14:57] error: z2m: Error while starting zigbee-herdsman
[2026-03-09 20:14:57] error: z2m: Failed to start zigbee-herdsman
[2026-03-09 20:14:57] error: z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2026-03-09 20:14:57] error: z2m: Exiting...
[2026-03-09 20:14:57] error: z2m: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
at ZStackAdapter.start (/app/node_modules/.pnpm/zigbee-herdsman@9.0.9/node_modules/zigbee-herdsman/src/adapter/z-stack/adapter/zStackAdapter.ts:107:27)
at Controller.start (/app/node_modules/.pnpm/zigbee-herdsman@9.0.9/node_modules/zigbee-herdsman/src/controller/controller.ts:145:29)
at Zigbee.start (/app/lib/zigbee.ts:70:27)
at Controller.start (/app/lib/controller.ts:111:29)
at start (/app/index.js:156:5)

[GigiPompieru]

While I do applaud your courage, auto-updating anything, especially coordinator fw sounds incredible to me.

That being said, are you connecting over USB or LAN? Does the SLZB log show any errors? Did you reach out to their support?

I'm asking since I also have a SLZB-06 running 20250321 and see no reason to update.

[mrmaximas]

@Ruud-cb please use stable Koenkk's 20250321, there is no reason to be a SLZB guinea pig.

[HansPeterDurand]

Good morning everybody,
In the meatime I flashed the SLZB-06 to version 20250321. Since then, the error in the logfile disappeared and Zigbee2MQTT works again.
From my point of view, there is on interesing aspect: The newer version (20260307) worked since the update seamlessly. Until yesterday morning. The whole configuration on SLZB-06 as well as Zigbee2MQTT hasn't been changed for months.

Up to know I do not understand the reason.

[mrmaximas]

@HansPeterDurand 20260307 from SLZB works with the x4 port speed (baudrate: 460800). I think this is an unsuccessful experimental fork.

[Ruud-cb]

While I do applaud your courage, auto-updating anything, especially coordinator fw sounds incredible to me.

That being said, are you connecting over USB or LAN? Does the SLZB log show any errors? Did you reach out to their support?

I'm asking since I also have a SLZB-06 running 20250321 and see no reason to update.

True, I thought I had it off, so definitely turned it off now.
I did look at the changelog though, higher boudrate might be interesting so once things stabilize a bit I might go for it.

[Ruud-cb]

@Ruud-cb please use stable Koenkk's 20250321, there is no reason to be a SLZB guinea pig.

I used that before, this one was more stable after a lot of trial and error.

[Speedy1098]

@Ruud-cb please use stable Koenkk's 20250321, there is no reason to be a SLZB guinea pig.

I have installed the 20250321 but i get these error:

Starting Zigbee2MQTT without watchdog.
[2026-03-10 11:50:43] info: z2m: Logging to console, file (filename: log.log)
[2026-03-10 11:50:43] info: z2m: Starting Zigbee2MQTT version 2.9.1 (commit #unknown)
[2026-03-10 11:50:43] info: z2m: Starting zigbee-herdsman (9.0.9)
[2026-03-10 11:50:43] info: zh:zstack:znp: Opening TCP socket with 192.168.178.22:6638
[2026-03-10 11:50:43] info: zh:zstack:znp: Socket connected
[2026-03-10 11:50:43] info: zh:zstack:znp: Socket ready
[2026-03-10 11:50:43] info: zh:zstack:znp: Writing CC2530/CC2531 skip bootloader payload
[2026-03-10 11:50:44] info: zh:zstack:znp: Skip bootloader for CC2652/CC1352
[2026-03-10 11:51:51] error: z2m: Error while starting zigbee-herdsman
[2026-03-10 11:51:51] error: z2m: Failed to start zigbee-herdsman
[2026-03-10 11:51:51] error: z2m: Check https://www.zigbee2mqtt.io/guide/installation/20_zigbee2mqtt-fails-to-start_crashes-runtime.html for possible solutions
[2026-03-10 11:51:51] error: z2m: Exiting...
[2026-03-10 11:51:51] error: z2m: Error: network commissioning timed out - most likely network with the same panId or extendedPanId already exists nearby (Error: AREQ - ZDO - stateChangeInd after

[GigiPompieru]

[2026-03-10 11:51:51] error: z2m: Error: network commissioning timed out - most likely network with the same panId or extendedPanId already exists nearby (Error: AREQ - ZDO - stateChangeInd after

I had this in the past. I ended up setting the network_key: GENERATE in configuration.yaml but this meant re-pairing all my devices.

Some people fixed it by switching off all the routers in their network and waiting 30 minutes, then the coordinator started OK.

[ronhoo]

Same issue here.

SNBZ_ERROR.txt

[Eismann]

Same here

[Nerivec]

If they switched the baudrate of the coordinator firmware to 460800, Z2M won't work anymore without also switching Z2M's config to that same baudrate...
https://www.zigbee2mqtt.io/guide/configuration/all-settings.html#serial

serial:
    # ...existing stuff...
    baudrate: 460800

Be sure to check what baudrate you have configured in the SMLight interface as well (TCP).

[tiagoaf5]

I had the same issue.
Followed @Nerivec tip and changed both in the SLZB-06 config the baudrate to 460800 (under "Z2M and ZHA") and then in the zigbee2mqtt config and everything is working again 🎉