SLZB-06M crashing every now and then

[Joshude]

What happened?

Every now and then (1h up to 24h) my Z2M crashes. I know there are some other reports with that, but those logs always state something else, so i'm trying with a new issue report. I'm not even sure if this repo is the right place for this.

[2025-11-09 14:42:47] error: 	zh:ember:uart:ash: Received ERROR from adapter, with code=ERROR_EXCEEDED_MAXIMUM_ACK_TIMEOUT_COUNT.
[2025-11-09 14:42:47] error: 	zh:ember:uart:ash: ASH disconnected | Adapter status: ASH_NCP_FATAL_ERROR
[2025-11-09 14:42:47] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-09 14:42:47] error: 	zh:ember: Adapter fatal error: HOST_FATAL_ERROR
[2025-11-09 14:42:47] error: 	z2m: Adapter disconnected, stopping
[14:45:20] INFO: Preparing to start...
[14:45:20] INFO: Socat not enabled
[14:45:21] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.

my config:

data_path: /config/zigbee2mqtt
socat:
  enabled: false
  master: pty,raw,echo=0,link=/tmp/ttyZ2M,mode=777
  slave: tcp-listen:8485,keepalive,nodelay,reuseaddr,keepidle=1,keepintvl=1,keepcnt=5
  options: "-d -d"
  log: false
mqtt: {}
serial:
  port: tcp://172.16.17.60:6638
  baudrate: 115200
  adapter: ember
  rtscts: false

The Z2M reboots and reconnects most of the times.

If there is anything else what i can provide please let me know, thanks!

What did you expect to happen?

No response

How to reproduce it (minimal and precise)

No response

Zigbee2MQTT version

2.6.3

Adapter firmware version

8.0.2 [GA] 20250220

Adapter

SLZB-06M

Setup

• SLZB-06M connected via PoE
• Z2M as HA add-on

Device database.db entry

No response

Debug log

45df7312_zigbee2mqtt_2025-11-09T14-20-03.054Z.log

Notes

No response

[Razer0ne]

Power up with usb. NOT poe. Poe can be unstable and cause this. try usb and LAN for network

[Joshude]

Power up with usb. NOT poe. Poe can be unstable and cause this. try usb and LAN for network

Thanks! I only have PoE Ports left (Which i cant disable, because the switch is unmanaged) Can i just additionally plug in the USB-power?

[Razer0ne]

since you have unmanaged switch, you can't turn off POE i think, use no POE port from switch, and use USB to power up smlight. sjekk in config on smlight Connection mode under Mode settings is on LAN mode.

[nstefy]

Power up with usb. NOT poe. Poe can be unstable and cause this. try usb and LAN for network

Explanation it's a bit odd

I have SLZB-MR4U PoE powered from UniFi switch USW Lite 16 PoE that runs 2 x z2m and having the same problem on ember network, ZStack has no problem
if it was a power issue shouldn't be both networks affected?

Didn't see any disconnection of coordinator in switch logs

on SLZB-MR4U logs are a lot of EFR32MG26 reconnection to z2m and not one problem on CC2674P10

see SLZB-MR4U config below

OH UniFi binding info

[Joshude]

I can confirm, changing to USB-power did not change a thing. My SLZB has no reboots, it's only the zigbee which crashes and restarts.
I changed to USB at around 8pm yesterday.

[2025-11-10 07:06:56] error: 	zh:ember:uart:ash: Received ERROR from adapter, with code=ERROR_EXCEEDED_MAXIMUM_ACK_TIMEOUT_COUNT.
[2025-11-10 07:06:56] error: 	zh:ember:uart:ash: ASH disconnected | Adapter status: ASH_NCP_FATAL_ERROR
[2025-11-10 07:06:56] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-10 07:06:56] error: 	zh:ember: Adapter fatal error: HOST_FATAL_ERROR
[2025-11-10 07:06:56] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-10 07:06:56] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-10 07:06:56] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-10 07:06:56] error: 	z2m: Adapter disconnected, stopping
[2025-11-10 07:06:56] error: 	z2m: MQTT error: write EPIPE
[2025-11-10 07:06:56] error: 	z2m: Not connected to MQTT server!
[2025-11-10 07:06:56] error: 	z2m: Not connected to MQTT server!
[2025-11-10 07:06:56] error: 	z2m: Cannot send message: topic: 'zigbee2mqtt/bridge/state', payload: '{"state":"offline"}
[07:07:02] INFO: Preparing to start...
[07:07:02] INFO: Socat not enabled
[07:07:03] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.
[2025-11-10 07:14:51] error: 	zh:ember:uart:ash: Received ERROR from adapter, with code=ERROR_EXCEEDED_MAXIMUM_ACK_TIMEOUT_COUNT.
[2025-11-10 07:14:51] error: 	zh:ember:uart:ash: ASH disconnected | Adapter status: ASH_NCP_FATAL_ERROR
[2025-11-10 07:14:51] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-10 07:14:51] error: 	zh:ember: Adapter fatal error: HOST_FATAL_ERROR
[2025-11-10 07:14:51] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-10 07:14:51] error: 	z2m: Adapter disconnected, stopping
[07:14:53] INFO: Preparing to start...
[07:14:53] INFO: Socat not enabled
[07:14:54] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.

[nstefy]

Looks like problem was resolved with firmware upgrade even is a Pre-release
Reed instruction before upgrade and select correct firmware for your chip

i used smlight_slzb06Mg26_zigbee_ncp_8.2.2.0_115200_sw_flow.gbl for EFR32MG26

this should be for slzb06m smlight_slzb06m_zigbee_ncp_8.2.2.0_115200_sw_flow.gbl
https://github.com/Nerivec/silabs-firmware-builder/releases/download/v2025.6.2-pre0/smlight_slzb06m_zigbee_ncp_8.2.2.0_115200_sw_flow.gbl

https://github.com/Nerivec/silabs-firmware-builder/releases/tag/v2025.6.2-pre0

no disconnection since upgraded

[Joshude]

Thanks, i'll give it a try. After upgrading the SLZB-OS to v3.1.0 it seemed to run better with less crashes but there were still crashes happening. Upgraded the zigbee to 20250602 8.2.2 and will test how it goes.
Thanks!

[Joshude]

Unfortunatly that hasn't resolved my issue. It's way more stable now but the error is still occuring.

[2025-11-18 17:32:43] error: 	zh:ember:uart:ash: Received ERROR from adapter, with code=ERROR_EXCEEDED_MAXIMUM_ACK_TIMEOUT_COUNT.
[2025-11-18 17:32:43] error: 	zh:ember:uart:ash: ASH disconnected | Adapter status: ASH_NCP_FATAL_ERROR
[2025-11-18 17:32:43] error: 	zh:ember:uart:ash: Error while parsing received frame, status=ASH_NCP_FATAL_ERROR.
[2025-11-18 17:32:43] error: 	zh:ember: Adapter fatal error: HOST_FATAL_ERROR
[2025-11-18 17:32:43] error: 	z2m: Adapter disconnected, stopping
[17:33:08] INFO: Preparing to start...
[17:33:08] INFO: Socat not enabled
[17:33:09] INFO: Starting Zigbee2MQTT...
Starting Zigbee2MQTT without watchdog.

[nstefy]

Does your adapter provide enough power?
Is a stand alone adapter or build in a socket (socket usb adapters r unreliable) ?

Had no disconnects with this firmware version.
A few people with SLZB-06M put it and didn't see any complains here

Nerivec/silabs-firmware-builder#54 (reply in thread)

[Nerivec]

The SoC at 80 Celsius (first post) looks pretty bad (I mostly see screenshots around 40-60). Something preventing proper airflow? Location sub-optimal?

[MSL-DA]

The SoC at 80 Celsius (first post) looks pretty bad (I mostly see screenshots around 40-60). Something preventing proper airflow? Location sub-optimal?

Same thought here. Here’s mine:

[Joshude]

Hm, now that you are mentioning it. But i can't really tell why thats the case. TX-power is at 20

€: Saw that there is a temp calibration feature. Will calibrate the temp now (will take a while cause i need to place a sensor there) and will report back

€2: Calibrated the temp, that issue is gone now. I swapped out the power supply for the usb-c and will see if that changes anything

[Nerivec]

How badly does that USB cable get pinched in that closed door? Can't push it through the vents instead (usb-c should be tiny)?

[MSL-DA]

If you hold your hand on it, does it feel warm? It is true that you can calibrate the device, but it sounds abnormal that it shows 40 degrees incorrectly.