Wiren Board 8 known issues

Hardware and software errata for Wiren Board 8. Check the affected model, batch and software version for each issue before applying its remedy.

ERRWB84001: Incompatibility with some Ethernet switches and routers

Affected devices: Wiren Board 8.4.3, batches v8.4.3A/4G, v8.4.3A/4G1 and v8.4.3A/4G2.

The Ethernet link comes up but no data passes when connected to certain switches or routers. Reducing the link speed to 10 Mbit/s restores operation. The CH182H Ethernet PHY is incompatible with some network devices, including MikroTik hAPac2 and the eero Dual-band 350 Mbps Wireless Router.

A controller with this PHY reports:

cat /sys/devices/platform/external-ethernet-phys/external-ethernet-phys:soft-mdio0/mdio_bus/gpio-0/gpio-0:00/phy_id
0x73719011

Workaround: use a compatible network device, or temporarily reduce the connection speed to 10 Mbit/s until the network device or controller can be replaced. Fixed in later controller revisions. Affected revision 8.4.3 controllers exhibiting this incompatibility qualify for warranty replacement.

ERRWB84002: Possible short circuit when installing the processor module

Affected batches: 8.4.3A/4G and v8.4.4A/4G.

Manufacturing tolerances on the processor module can allow its contact pads to become misaligned with the SO-DIMM connector contacts. Excessive movement toward the side-module connector can cause a short circuit on some devices. Positioning the module toward the SD-card slot does not cause this problem.

Workaround: a spacer is fitted to the connector latch nearest the side-module connector to hold the processor module toward the SD-card slot. The SO-DIMM connector also bears a Do not remove label. If the spacer is lost, position the module fully toward the SD-card slot when installing it. Fixed in later controller revisions.

ERRWB84003: Rules engine instability

Affected devices: Wiren Board 8.4.3, batch 8.4.3A/4G, manufactured before 23 May 2024.

The installed rules engine has incomplete WB8 support and may operate unreliably. Update the software:

apt update
apt upgrade

Without Internet access, download the latest stable FIT image, update the controller and also copy the image to /mnt/data/.wb-restore/factoryreset.fit. Fixed in newer firmware.

ERRWB84004: MQTT driver instability

Affected devices: Wiren Board 8.4.3, batches 8.4.3A/4G and 8.4.3A/4G1, manufactured before 11 June 2024.

Incomplete WB8 support in the installed firmware may cause unstable MQTT-driver operation. Update the software:

apt update
apt upgrade

Without Internet access, download the latest stable FIT image, update the controller and also copy the image to /mnt/data/.wb-restore/factoryreset.fit. Fixed in newer firmware.

ERRWB84005: Ethernet stops after a kernel update and reboot

Affected devices: Wiren Board 8.4.3 from any batch, updated between 16 and 19 August 2024, with linux-image-wb8 version 6.8.0-wb100.

An error in the DTS file configures Ethernet incorrectly. After an APT kernel update or FIT-image update and reboot, the Ethernet ports stop working.

Update with apt update && apt upgrade. Without Internet access, install the latest stable FIT image through Debug Network, Wi-Fi or a USB drive; no additional copy of the image is needed. Fixed in linux-image-wb8 version 6.8.0-wb101 and later.

ERRSUPERCAP0001: 36 V supply limit with affected supercapacitor modules

Affected modules: WBMZ4-SUPERCAP, WBMZ3-SUPERCAP and WBMZ2-SUPERCAP.

A controller fitted with an affected module must not be supplied above 36 V. The module's output converter uses a diode rated for a maximum of 40 V. A higher controller supply voltage can break down this diode, damaging the backup module and possibly the controller.

Workaround: limit the controller supply to 36 V. If backup power is required with a higher supply voltage, request a warranty module replacement. Fixed in WBMZ6-SUPERCAP v6.1 and later and WBMZ4-SUPERCAP v4.3 and later.

ERRWB74004: GSM modem disconnects due to external electromagnetic interference

Affected devices: Wiren Board 7.4 and 8.4 with WBC2-4G modem boards earlier than version 3.7.

Electromagnetic contactors close to the controller can induce interference that disconnects the modem. The USB bus used for modem communication is sensitive to this interference. Typical kernel messages include:

option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
option 3-1:1.2: device disconnected

ModemManager reports timed-out serial commands and repeated port timeouts, then releases the modem's USB ports. The service automatically restarts the modem.

Workarounds:

• Move sources of arcing interference as far from the controller as possible.
• Fit a suitable snubber across the relay contacts controlling the contactor coil. The example values are a 100 Ω, 1 W resistor in series with a 0.1 µF, 1000 V capacitor. Suppressing contact arcing substantially reduces the interference.
• A short, thick-wire jumper under 1 cm long between the modem-board ground near the antenna connector and the nearest controller-board ground also resolves the issue, but requires careful board modification and soldering.

Fix: modem-board version 3.7 adds an extra grounding pogo pin.

ERRWBC001: GSM modem disconnects due to its own electromagnetic interference

Affected devices: WBC2-4G modems earlier than revision v3.7A.

The modem disappears from the system; rebooting helps only briefly or not at all. With a distant base station, weak signal and the standard short antenna, modem transmissions can interfere with the USB controller, disconnecting USB devices, particularly the modem itself.

The kernel log shows modem serial ports disconnecting and reconnecting, for example:

option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
option 3-1:1.2: device disconnected
usb 3-1: new high-speed USB device number 8 using ehci-platform
usb 3-1: GSM modem (1-port) converter now attached to ttyUSB0

The service automatically restarts the modem. A short, thick-wire jumper under 1 cm between the modem ground near the antenna connector and the nearest controller-board ground resolves the issue but requires careful soldering. Revision v3.7A and later add a pogo pin connecting the modem ground plane to the controller's USB-A connector shell to suppress interference.

Improve reception, for example by raising or relocating the antenna. If this is ineffective or impossible, request warranty replacement with a modem version 3.7 or later.

ERRWB84006: Periodic controller reboots

Affected devices: all Wiren Board 8.4.3 controllers manufactured before 11 September 2024.

The controller reboots unexpectedly. The debug console shows Kernel panic - not syncing: hung_task: blocked tasks; journald contains no corresponding entries. A software error sends an opcode 0 command to the eMMC storage, after which the Linux driver stops sending further commands.

Update with apt update && apt upgrade. Without Internet access, install the latest stable FIT image through Debug Network, Wi-Fi or a USB drive; an additional image copy is not needed. Fixed in release wb-2407 with wb-rules 2.20.17 or later and wb-mqtt-confed 1.14.11 or later.

ERRWB84007: Factory reset fails

Affected devices: Wiren Board 8.4.3 flashed with the FIT image dated 13 November 2024, 202411131702_wb-2410_bullseye_wb8x.fit, which has been withdrawn.

After installing this image by any method, a factory reset using the internal image without external media resizes the root partition to 1 GB and leaves the controller unable to start or update normally. The image incorrectly restores the obsolete A/B partition layout, no longer supported by the rest of the software.

Remedy: perform a factory reset from external media using the latest stable FIT image. Fixed in newer firmware.

ERRWB84008: APT finds no updates

Affected devices: Wiren Board 8.4.4, batch 8.4.4B/2G 1.2A-2G, manufactured on 13 August 2024.

Factory firmware was pinned to a specific release rather than the stable channel, so apt update && apt upgrade did not find new stable releases. Install a current FIT image or run wb-release -t stable -y. Corrected FIT images are available and the affected images have been withdrawn.

ERRWBEC0001: Controller cannot be switched off

Affected devices: Wiren Board 7.4 and 8.4 with WBEC firmware 2.0.0 or 2.0.1, whether installed manually or supplied with wb-2410 between 14 and 22 November 2024. Affected batches include 7.4.4D/2GCA, 7.4.4E/1G, 7.4.4E/2GC, 8.4.4D/2G and 8.4.4E/4G.

A WBEC sleep-mode defect prevents shutdown using the button, poweroff or rtcwake. The controller can power on again spontaneously after shutdown and power removal. Continuously operating controllers are not affected during normal operation.

Update WBEC firmware. Fixed in WBEC 2.0.2; controllers shipped after 25 November 2024 are unaffected.

ERRWB8M0001: Incorrect SIM-slot labels

Affected batches: WB8M v8.5.2A/M through v8.5.2D/M.

The front-panel SIM numbers were reversed. SIM1 is on the left; SIM2 is nearer the enclosure edge. Move the card to the other slot if necessary. Corrected in subsequent batches.

ERRWB84009: Unstable RS-485 port operation

Affected devices: all Wiren Board 8 controllers covered by this erratum.

The controller sometimes fails to receive a Modbus response on the first attempt. The wb-mqtt-serial log may contain:

WARNING: [modbus] failed to read 1 input(s) @ 123 of device </dev/ttyRS485-1 115200 8 N 2> modbus:130: Serial protocol error: request timed out

Using minicom on the controller's RS-485 ports can also stop reception until reboot. The cause is incorrect switching of RS-485 transceiver modes in the Linux kernel.

Workaround: avoid minicom on the controller's RS-485 ports until the fix is available. Reboot to restore ports affected after using minicom. A software fix is planned.

ERRWB840010: Cloud connection missing after flashing

Affected devices: Wiren Board 8 controllers updated to wb-2507 using FIT images between 5 and 9 August 2025.

Incorrect early wb-2507 images omitted the cloud provider. Cloud information is missing from the System page and running wb-cloud-agent returns No one provider was found.

Add the provider manually:

wb-cloud-agent add-provider https://wirenboard.cloud

Fixed in controller software from 11 August 2025. Run apt update; apt upgrade -y or install a current FIT image.

ERRWB8001: Empty configuration files on new controllers

Affected devices: Wiren Board 7/8 manufactured after October 2025, and Wiren Board 7/8 with affected software installed between 1 October 2025 and 30 July 2026.

Interrupting power during the first or second boot of a new or factory-reset controller can leave /mnt/data/etc/wb-*.conf files empty because they have not been flushed to flash storage. The web interface then reports parsing errors, such as:

Server error: Failed to parse JSON /etc/wb-mqtt-serial.conf:* Line 1, Column 1 Syntax error: value, object or array expected. (-32000)

Connect by SSH and list empty files:

find /mnt/data/etc -maxdepth 1 -type f -name 'wb-*.conf*' -empty

Fixed in wb-2606 dated 31 July 2026. Update and reboot; empty files will be populated with factory defaults and existing configuration files will remain unchanged:

apt update
apt upgrade
reboot

If updating is temporarily unavailable, replace the empty files in /mnt/data/etc/ with valid files from a working controller using WinSCP or scp, or perform a factory reset. A factory reset erases all controller data. Update at the first opportunity.

ERRWB85001: Missing reverse-polarity protection on 1-Wire ports

Affected devices: Wiren Board 8.5.3 batches v8.5.3B through v8.5.3G, v8.5.3J/2G and v8.5.3J/4G; WB-MS sensors in batches v4.4K, v4.4L and v4.4L/2.

An incorrectly specified component was fitted in the 1-Wire protection circuit. Other protection remains, but negative voltage is not blocked. Negative voltage can result from wiring mistakes or interference from nearby power-switching equipment. It can damage the 1-Wire port or the entire device.

Check 1-Wire connections before powering on, keep the device away from interference sources and follow 1-Wire bus wiring recommendations. Warranty replacement is available. Fixed in Wiren Board 8.5.3 from batch v8.5.3K and WB-MS from batch v4.4M.

ERRWB8002: ATECC security-chip communication failures

Affected devices: Wiren Board 8 with linux-wb earlier than 6.8.0-wb161 and releases before wb-2606.

Failures affect Wiren Board Cloud and other ATECC-dependent services. A typical log message is:

RuntimeError: Cert /var/lib/wb-cloud-agent/device_bundle.crt.pem and key ATECCx08:00:02:C0:00 seem to be inconsistent (possibly because of CPU board missmatch)!

Two concurrency issues cause the fault. The bit-banged I2C driver uses GPIO rather than a hardware I2C controller; simultaneous ATECC access and access to other GPIO in the same bank can put I2C lines in an incorrect state. In addition, unsynchronized access from multiple services can interleave requests and deliver responses to the wrong client.

If ATECC is unresponsive, reboot to restore it. Update to wb-2606, which fixes the kernel driver (linux-image-wb8 6.8.0-wb161) and the affected services.

ERRWB8003: Possible RAM faults

Affected devices: Wiren Board 8 (WB8-2G-16G-IND) from batches 8.5.3G/2G2, 8.5.3G/4G5, 8.5.3J/2G, 8.5.3J/2G2, 8.5.3J/4GD, 8.5.3K/2G, 8.5.3K/2G1, 8.5.3K/2G1D and 8.5.3K/2GD; Wiren Board 8M (WB8M-2G-16G-IND) batch v8.5.3G/2GM.

A small number of controllers may develop random faults under intensive RAM load, increasing over time: services crash and restart without an apparent cause, package updates or file checks report checksum errors, or the controller reboots after a kernel panic. After reboot it may work normally for a while before the faults return.

systemd[1]: example.service: Main process exited, code=killed, status=4/ILL

The status can also be 11/SEGV. Extended full-load testing identified one defective RAM chip whose errors increased exponentially over several hours within a limited memory-address range. Similar faults in other units from these batches are considered unlikely but cannot be ruled out.

Test suspected RAM with the preinstalled memtester. Stop the controller workload first because the test uses almost all available memory.

1. Run free -m and read the available column.
2. Test 100 MB less than that value. For example, if 1300 MB is available, run memtester 1200M 1.

A full test may take about an hour. All result lines should end in ok. If any show FAILURE, the controller qualifies for warranty replacement.

ERRWBUSB0001: Debug USB console stops receiving

Affected devices: all Wiren Board 7 and Wiren Board 8 revisions, including Wiren Board 8M.

Debug-console output stops, although the controller continues working and accepting commands. The HT42B534 buffer overflows if the computer port is closed or its application does not read fast enough. Tests triggered this with 130 bytes while the port was closed; with the port open, the threshold depends on computer-side buffering.

Reproducing the issue

Connect the console to a Linux computer and configure minicom. Run controller-side commands as root over SSH.

1. On the computer, open the port, replacing the device path as needed: minicom -D /dev/ttyACM0 -b 115200 -8 -o.
2. Exit without resetting the port: Ctrl+A, Q, then confirm.
3. On the controller, run printf '%0300d\n' 0 > /dev/ttyS0.
4. Reopen minicom with the same command. On the controller, run echo HOLTEK_TEST > /dev/ttyS0. Old data may appear, but HOLTEK_TEST does not.

Workaround

In minicom, change stop bits from 1 to 2 and back: Ctrl+A, then P → X → Enter; then Ctrl+A, P → W → Enter. Do not send console commands while switching.

On Windows 11, closing and reopening the COM port restored reception in testing. In PuTTY, close the window and reopen the serial connection. In MobaXterm, close the Serial tab and reopen the saved session.

Repeat the HOLTEK_TEST command; its output should now appear. Lost messages cannot be recovered. Reduce recurrence by keeping the port open in an application that continuously reads it. A hardware fix is planned for future Wiren Board 8 versions.

ERRWB840011: MOD1/MOD2 ports hang or resend old RS-485 data

Affected devices: Wiren Board 8.5.x with linux-wb 6.8.0-wb159 or earlier.

When MOD1 and MOD2 are polled simultaneously and either port is closed or reset, for example during a wb-mqtt-serial restart or port reconfiguration, both ports may stop polling until reboot.

If a transmit-buffer flush (tcflush()) or port closure overlaps communication with the embedded controller, the port may resend up to 4 KB of deleted data. On RS-485 this appears as old Modbus frames being transmitted again; closing the port takes about 10 seconds.

Two races in wbec-uart access the transmit ring buffer without the port lock. During closure, the driver can access an already freed buffer, crashing the embedded-controller interrupt thread and permanently holding the shared MOD1/MOD2 mutex, leaving uninterruptible D-state processes. A transfer started before a flush can also update the already-reset buffer, restoring deleted data and retransmitting it.

Reboot if the ports have already hung. Until updating the kernel, minimize wb-mqtt-serial restarts and port reconfiguration on controllers polling both MOD1 and MOD2. Run apt update; apt upgrade -y. Fixed in linux-image-wb8 6.8.0-wb160 and later.