Running EmberZNet 8.x on the Lidl Silvercrest Gateway¶

Background: The Series 1 Deprecation Problem¶

The Lidl Silvercrest Gateway uses a Silicon Labs EFR32MG1B chip, which is a Series 1 device.

In 2024, Silicon Labs discontinued support for Series 1 chips in newer versions of their Zigbee stack:

SDK	EmberZNet	Series 1 Support
Gecko SDK 4.x	7.5.x	✅ Last supported
Simplicity SDK 2025.x	8.x	❌ Series 2 only

This means users of Series 1 devices (including the Lidl gateway) are stuck on EmberZNet 7.5.x if running the Zigbee stack directly on the chip using the traditional NCP (Network Co-Processor) architecture.

The Solution: RCP Architecture¶

We found a workaround using the RCP (Radio Co-Processor) architecture:

Traditional NCP:  Zigbee Stack runs ON the EFR32 chip
RCP Architecture: Zigbee Stack runs ON a Linux host (x86 PC, Raspberry Pi, etc.)

In RCP mode, the EFR32 chip only handles the 802.15.4 radio PHY/MAC layer. The EmberZNet stack runs on a separate Linux host via zigbeed, communicating with the RCP through cpcd (Co-Processor Communication daemon).

Key insight: The RCP firmware for Series 1 (built from Gecko SDK 4.5.0) is compatible with zigbeed from Simplicity SDK 2025.x running EmberZNet 8.x!

+-------------------+    UART    +-------------------+   Ethernet   +---------------------+
|  EFR32MG1B (RCP)  |   460800   |  Lidl Gateway     |    TCP/IP    |  Host (x86/ARM)     |
|                   |   baud     |  (RTL8196E)       |              |                     |
|  802.15.4 PHY/MAC |<---------->|                   |<------------>|  cpcd               |
|  + CPC Protocol   |   ttyS0    |  in-kernel UART   |   port 8888  |    |                |
|                   |            |  bridge (kernel)  |              |    v                |
|  Gecko SDK 4.5.0  |            |                   |              |  zigbeed 8.2.2      |
|                   |            |                   |              |  (EmberZNet 8.x)    |
+-------------------+            +-------------------+              |    |                |
                                                                    |    v                |
                                                                    |  Zigbee2MQTT        |
                                                                    +---------------------+

CPC transport — native TCP bus. cpcd is built with a native bus_type: TCP (carried as cpcd/tcp-bus.patch, applied automatically by build_cpcd.sh). With it, cpcd connects directly to the gateway's in-kernel UART↔TCP bridge on TCP:8888 and reconnects on its own — no intermediate socat PTY in front of cpcd. The Docker stack (docker/cpcd-zigbeed/) uses this directly. The native rcp-stack flow documented below still front-ends cpcd with a socat PTY (socat-cpc-rcp) and uart_device_* keys; moving it onto the TCP bus is a follow-up. To use the TCP bus with a hand-rolled cpcd.conf, set bus_type: TCP plus tcp_server_address / tcp_server_port instead of uart_device_file / uart_device_baud.

Installation Guide¶

Prerequisites¶

Host machine: x86_64 PC, Raspberry Pi 4/5, or any Linux host
Lidl gateway: Already flashed with RCP firmware; kernel 6.18 with rtl8196e-uart-bridge armed (default via S50uart_bridge)
Network: Direct Ethernet cable between host and gateway (strongly recommended)

Step 1: Install Build Dependencies¶

sudo apt install cmake build-essential socat git

Step 2: Install Silicon Labs Tools¶

Follow the instructions in 1-Build-Environment to install slc-cli and ARM GCC toolchain:

cd 1-Build-Environment
sudo ./install_deps.sh

Step 3: Build and Install cpcd¶

cd 2-Zigbee-Radio-Silabs-EFR32/25-RCP-UART-HW/cpcd
./build_cpcd.sh         # Clone, build, install to /usr/local

Step 4: Build and Install zigbeed 8.2.2¶

cd 2-Zigbee-Radio-Silabs-EFR32/25-RCP-UART-HW/zigbeed-8.2.2
./build_zigbeed.sh      # Downloads SDK automatically, build, install

Note: On first run, the script automatically downloads Simplicity SDK 2025.6.3 from GitHub (~1.5 GB).

Step 5: Setup rcp-stack Manager¶

The rcp-stack script needs its companion files (scripts/, systemd/, examples/), so it must be run from the cloned repository.

Option A: Create an alias (recommended)

Add to your ~/.bashrc:

alias rcp-stack='/path/to/hacking-lidl-silvercrest-gateway/2-Zigbee-Radio-Silabs-EFR32/25-RCP-UART-HW/rcp-stack/bin/rcp-stack'

Then reload:

source ~/.bashrc

Option B: Run directly from the repo

./2-Zigbee-Radio-Silabs-EFR32/25-RCP-UART-HW/rcp-stack/bin/rcp-stack up

Step 6: Configure¶

First run creates the config file:

rcp-stack up
# -> Creates ~/.config/rcp-stack/rcp-stack.env
# -> Copies helper scripts to ~/.config/rcp-stack/bin/
# -> Links systemd units to ~/.config/systemd/user/
# -> Will fail, prompting you to edit the config

Edit the configuration:

nano ~/.config/rcp-stack/rcp-stack.env

Set your gateway IP and commands:

RCP_ENDPOINT=tcp://192.168.1.88:8888
CPCD_COMMAND='cpcd -c "$HOME/.config/rcp-stack/cpcd.conf"'
ZIGBEED_COMMAND='zigbeed -r "spinel+cpc://$CPC_INSTANCE_NAME?iid=1&iid-list=0" -p "$ZIGBEED_PTY" -d 1 -v 0'

Copy the cpcd config:

cp /path/to/hacking-lidl-silvercrest-gateway/2-Zigbee-Radio-Silabs-EFR32/25-RCP-UART-HW/rcp-stack/examples/cpcd.conf.example ~/.config/rcp-stack/cpcd.conf

Important: Edit cpcd.conf and set the correct baudrate (must match RCP firmware):

uart_device_baud: 460800

Step 7: Start the Stack¶

rcp-stack up

This starts the complete chain: 1. socat-cpc-rcp — TCP to PTY bridge 2. cpcd — CPC daemon 3. zigbeed — EmberZNet 8.2.2 stack 4. Zigbee2MQTT (if configured)

Step 8: Configure Zigbee2MQTT¶

In configuration.yaml:

serial:
  port: /tmp/ttyZ2M
  adapter: ember

Verification¶

Check the rcp-stack logs:

journalctl --user -u zigbeed.service -f

Then start Zigbee2MQTT. You should see EmberZNet 8.2.2 (EZSP 18):

 > zigbee2mqtt@2.7.2 > node index.js  Starting Zigbee2MQTT [2026-01-22 16:49:34] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:35] info: [2026-01-22 16:49:40] info: [2026-01-22 16:49:40] info: [2026-01-22 16:49:45] info: [2026-01-22 16:49:45] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info: [2026-01-22 16:49:47] info:

lineno-17-1">$ pnpm start start /opt/zigbee2mqtt without watchdog. z2m: Logging to console, file (filename: log.log) z2m: Starting Zigbee2MQTT version 2.7.2 (commit #3a49c957) z2m: Starting zigbee-herdsman (8.0.1) zh:ember: Using default stack config. zh:ember: ======== Ember Adapter Starting ======== zh:ember:ezsp: ======== EZSP starting ======== zh:ember:uart:ash: ======== ASH Adapter reset ======== zh:ember:uart:ash: RTS/CTS config is off, enabling software flow control. zh:ember:uart:ash: Serial port opened zh:ember:uart:ash: ======== ASH starting ======== zh:ember:uart:ash: ======== ASH Adapter reset ======== zh:ember:uart:ash: ======== ASH starting ======== zh:ember:uart:ash: ======== ASH Adapter reset ======== zh:ember:uart:ash: ======== ASH starting ======== zh:ember:uart:ash: ======== ASH connected ======== zh:ember:uart:ash: ======== ASH started ======== zh:ember:ezsp: ======== EZSP started ======== zh:ember: Adapter version info: {"ezsp":18,"revision":"8.2.2 [GA]","build":436,"major":8,"minor":2,"patch":2,"special":0,"type":170} zh:ember: [STACK STATUS] Network up. zh:ember: [INIT TC] Adapter network matches config. zh:ember: [CONCENTRATOR] Started source route discovery. z2m: zigbee-herdsman started (resumed) z2m: Coordinator firmware version: '{"meta":{"build":436,"ezsp":18,"major":8,"minor":2,"patch":2,"revision":"8.2.2 [GA]","special":0,"type":170},"type":"EmberZNet"}'

Key indicators of success: - EZSP started with protocol version 18 - Adapter version info showing 8.2.2 [GA] - [STACK STATUS] Network up. - Coordinator firmware version confirming EmberZNet 8.2.2

Quick Reference¶

Command	Description
`rcp-stack up`	Start the complete chain
`rcp-stack down`	Stop cleanly
`rcp-stack status`	Show service status
`rcp-stack doctor`	Full diagnostics

Troubleshooting¶

Diagnostic Commands¶

# Quick status of all services
rcp-stack status

# Full diagnostics (services, sockets, PTYs, config files)
rcp-stack doctor

# Detailed logs for a specific service
journalctl --user -u cpcd-bringup.service -n 50 --no-pager
journalctl --user -u zigbeed.service -n 50 --no-pager

# Follow logs in real-time
journalctl --user -u cpcd-bringup.service -f

cpcd fails with "Baudrate mismatch"¶

Symptom:

FATAL: Baudrate mismatch (230400) on the daemon versus (460800) on the secondary

Cause: The baudrate in cpcd.conf doesn't match the RCP firmware.

Solution: Edit ~/.config/rcp-stack/cpcd.conf and set the correct baudrate:

uart_device_baud: 460800

Then restart:

rcp-stack down
rcp-stack up

cpcd fails with "Start request repeated too quickly"¶

Symptom: systemd stops retrying after multiple failures.

Solution: Check the actual error in the logs:

journalctl --user -u cpcd-bringup.service -n 50 --no-pager

Then fix the underlying issue and restart:

rcp-stack down
rcp-stack up

Cannot connect to RCP endpoint¶

Symptom:

Cannot connect to RCP endpoint 192.168.1.88:8888

Checks: 1. Gateway is powered on 2. In-kernel UART bridge is armed on the gateway (cat /sys/module/rtl8196e_uart_bridge/parameters/armed → 1) 3. Network connectivity: nc -zv 192.168.1.88 8888 4. Correct IP in ~/.config/rcp-stack/rcp-stack.env

CPC sockets not created¶

Solution: Clean up and restart:

rcp-stack down
rm -rf /dev/shm/cpcd/cpcd_bringup
rcp-stack up

zigbeed fails with token error¶

Symptom: Token version mismatch (v1 vs v2) when upgrading from EmberZNet 7.x to 8.x.

Solution:

rm ~/.local/state/rcp-stack/zigbeed/host_token.nvm
rcp-stack down
rcp-stack up

Checking service health¶

A healthy stack looks like this:

● socat-cpc-rcp.service      active (running)
● cpcd-bringup.service       active (running)
● zigbeed.service            active (running)
● socat-zigbeed-pty.service  active (running)

And the logs should show:

Zigbeed started
RCP version: SL-OPENTHREAD/2.4.7.0_GitHub-...; EFR32; ...
Zigbeed Version: GSDK 8.2.2 - ...

Important Notes¶

Direct Ethernet connection: The CPC protocol is sensitive to latency. Avoid WiFi or congested networks.
Token migration: If upgrading from EmberZNet 7.x to 8.x, delete the old token:
```
rm ~/.local/state/rcp-stack/zigbeed/host_token.nvm
```
Baud rate: 460800 baud is the pre-built firmware default. All bauds up to 460800 (POSIX-capped by cpcd) run through the in-kernel UART bridge on kernel 6.18 (see baudrate guide).

This workaround allows you to run the latest EmberZNet 8.x stack on your Lidl gateway despite Silicon Labs' Series 1 deprecation!