Drops from MQTT after 12 hours, and SSH is unreachable from the start

[llak0]

Summary

1.0.194 on a CZ-TAW1B disconnects from the MQTT broker after 12 to 24 hours. Before this, it handles commands correctly and seems to have dropbear running according to ps, but SSH connection attempts are refused.

Symptoms

• Attempts to connect via SSH are refused (ssh: connect to host <CZ-TAW1B_IP_ADDRESS> port 22: Connection refused), even before disconnecting from the MQTT broker / crashing.
• Keeping the Reset button pressed, the middle LED flashes blue, and returns to white after releasing the button. This does not reconnect the device to the MQTT broker.
• When the device has crashed, the Link (bottom) LED is also off, not flashing green after it crashes.
• Before the device crashes, it publishes Offline to panasonic_heat_pump/commands/LWT

What works

• Heishamon successfully connects to the configured MQTT server, and handles commands correctly (including panasonic_heat_pump/commands/OSCommand), until the MQTT connection drops.
• The device is correctly integrated with Home Assistant, using kamaradclimber/heishamon-homeassistant.

Unsuccessul attempts to investigate/fix

• Tried to start /usr/sbin/dropbear -E, via MQTT. This fails as port 22 is in use.
• Tried to stop and start the dropbear service with /etc/init.d/dropbear stop and /etc/init.d/dropbear start. This does not have an effect.
• Tried to follow the steps to perform a first boot, necessary in previous versions. The device disconnects from the MQTT broker, and doesn't reconnect.

Steps to reproduce

1. Install version 1.0.194 on a CZ-TAW1B device connected via Ethernet, with no prior WiFi configuration, using the following configuration file (GoHeishaMonConfig.new):

Readonly=true
Device="/dev/ttyUSB0"
Loghex=true
ReadInterval=1
Aquarea2mqttCompatible=false
Aquarea2mqttPumpID=""
Mqtt_topic_base="panasonic_heat_pump/main"
Mqtt_set_base="panasonic_heat_pump/commands"
ForceRefreshTime=300
MqttServer="<MQTT_BROKER_IP_ADDRESS>"
MqttPort="1883"
MqttLogin="<MQTT_BROKER_USERNAME>"
MqttPass="<MQTT_BROKER_PASSWORD>"
SleepAfterCommand=1
MqttClientID="GoHeishaMon-pub"
MqttKeepalive=60
EnableCommand=true
HAAutoDiscover=true

2. Wait 12 to 24 hours.
3. When GoHeishamon has crashed, it will have published Offline to panasonic_heat_pump/commands/LWT

Steps to mitigate

The only known way to recover from this state is keeping all 3 buttons pressed, until it starts the stock firmware and all 3 lights are green, and then reinstalling GoHeishamon.