Resolving LOGO! Soft Comfort PC to LOGO Download Failed on Linux

1. Problem Statement and Failure Symptom

The Siemens LOGO! 0BA8 Standard controller, when programmed from a Linux workstation running LOGO!Soft Comfort V8.0, V8.1, or V8.2, can reach the point of an Ethernet handshake on the same subnet (ICMP echo passes both directions between 192.168.1.56 and 192.168.1.251) but the programming software refuses the program transfer with the exact dialog message:

Download PC → LOGO!  Failed

The diagnostic footprint is specific and recognizable:

• Both PC and LOGO! are configured with static IPv4 addresses and a /24 subnet mask (255.255.255.0).
• Bidirectional ICMP echo (ping) is healthy from both ends, including from the LOGO! to the PC.
• On a separate subnet (where the two devices cannot ping each other) the transfer dialog opens but no LOGO! is found on the network scan, as expected.
• The same LOGO!Soft Comfort V8.x installation, when copied to a Windows partition, transfers programs without error to the same physical LOGO! 0BA8. This eliminates the cable, the switch, and the LOGO! hardware as the failure point and isolates the cause to the Linux runtime of the Siemens software.

This is a known class of failure for LOGO!Soft Comfort on Debian-derived Linux distributions. The fix does not require a different PC, a different cable, or a firmware change on the LOGO! 0BA8. Three independent root causes are documented in the field, and all three are addressed in the procedure below.

2. Affected Environment and Software Versions

3. Root Cause Analysis

Three independent root causes have been reproduced on the same LOGO! 0BA8, same cable, same subnet, and same static IP configuration. They are not mutually exclusive: a workstation that fails after Fix 1 is applied will frequently still fail until Fix 2 is also applied.

3.1 Routing Conflict via Active WiFi Interface

When the Linux PC has both an Ethernet interface (eth0) and an active WiFi interface (wlan0), the kernel routing table can install a default route through the WiFi adapter with a lower metric than the Ethernet default route. The user-space application then sends the LSC transfer TCP segments out the WiFi interface, while the LOGO! 0BA8 responds on the Ethernet segment. The transfer fails with a TCP timeout that the application surfaces as Download PC → LOGO! Failed. ICMP ping succeeds because ping uses the ICMP echo subsystem which is interface-bound in the opposite direction and appears to work inconsistently.

3.2 Missing SUSE-Style Network Skeleton Files

LOGO!Soft Comfort V8.x for Linux is built on the SUSE RPM package conventions. During network interface discovery the application reads the contents of /etc/sysconfig/network/ifcfg-eth0 and /etc/sysconfig/network/ifcfg-wlan0 to determine the active interface list. On Debian-family distributions this directory and these files do not exist, and the application aborts the network probe silently. Creating empty placeholder files satisfies the probe and allows the program transfer to proceed.

3.3 Java Runtime Mismatch

The LSC V8.x Linux transport stack is built against a specific Java runtime. OpenJDK builds shipped with Ubuntu and Linux Mint will launch the GUI but will fail the LSC internal discovery and transfer protocol with no error in the GUI. Siemens officially documents Support Entry 25447431 endorsing Amazon Corretto 11.0.13.8.1 as the supported JRE for the LOGO!Soft Comfort V8.x Linux runtime.

4. Pre-Flight Network Checklist

Before applying any fix, capture the current state so that the three fixes below can be applied in isolation if needed. All commands require a root shell or sudo:

1. Verify the PC and LOGO! share a /24 subnet:

   ip -4 addr show | grep -E 'inet |state UP'
   ping -c 4 192.168.1.251

2. Verify the LOGO! responds on its Ethernet port. The 0BA8 ships with IP 192.168.1.251 by default; if the user has changed it, set the PC to a same-subnet address:

   sudo ip addr add 192.168.1.56/24 dev eth0
   sudo ip link set eth0 up

3. Check the kernel routing table for two default routes:

   ip route show default

   If two default via entries appear, the routing-conflict root cause (3.1) is active.
4. Confirm the active interfaces and their states:

   ip link show
   nmcli device status

5. Capture the LOGO! MAC from the device front panel sticker or from the discovery:

   arp -n | grep 192.168.1.251

6. Capture a baseline TCP attempt against the LOGO! transfer port to confirm the failure is not a physical-layer issue:

   timeout 3 bash -c 'cat </dev/tcp/192.168.1.251/1352' || echo "no service"

   The LSC transfer service listens on TCP/1352; a refusal here means the LOGO! is reachable but not yet in server mode, which is normal until a transfer is initiated.

5. Fix 1: WiFi Interface Isolation

This is the fastest fix and the most commonly reported resolution in the field. It addresses root cause 3.1.

5.1 Disable WiFi via NetworkManager

1. Right-click the NetworkManager tray icon on Cinnamon, GNOME, KDE, or XFCE.
2. Select Enable Wi-Fi to toggle it off (uncheck).
3. Verify the wireless interface is administratively down:

   nmcli radio wifi off
   ip link show wlan0   # state should be DOWN

5.2 Disable WiFi via rfkill (Hard Block)

If the toggle does not stick, hard-block the wireless radio at the kernel level:

sudo rfkill block wifi
ip link show wlan0   # state should be DOWN, rfkill list confirms hard block

5.3 Disable WiFi via Interface Teardown

For headless or scripted environments:

sudo ip link set wlan0 down

5.4 Persistent WiFi Disable on Boot

For Linux Mint 22.3 / Ubuntu 22.04+ with NetworkManager, create a NetworkManager dispatcher rule:

sudo tee /etc/NetworkManager/dispatcher.d/pre-down.d/99-logo-wifi-off <<'EOF'
#!/bin/sh
if [ "$1" = "wlan0" ]; then
  exit 0
fi
nmcli radio wifi off
EOF
sudo chmod +x /etc/NetworkManager/dispatcher.d/pre-down.d/99-logo-wifi-off

6. Fix 2: Sysconfig Network Skeleton Files

This fix addresses root cause 3.2 and is the most reliable of the three. It is mandatory on Debian-family distributions and harmless on SUSE-family. The exact commands verified in the field are:

sudo mkdir -p /etc/sysconfig/network
sudo touch /etc/sysconfig/network/ifcfg-eth0
sudo touch /etc/sysconfig/network/ifcfg-wlan0

The files must exist before LSC V8.x starts its network probe. They are intentionally left empty; the LSC runtime only checks for their presence. If the LOGO! workstation is also running systemd-networkd or netplan, no conflict is introduced because the LSC probe only reads the file path, not the network manager state.

6.1 Verify the Skeleton Files Are Visible to the Process

ls -l /etc/sysconfig/network/
stat /etc/sysconfig/network/ifcfg-eth0
stat /etc/sysconfig/network/ifcfg-wlan0

6.2 Persist Across Reboots

The touch and mkdir commands survive reboots because the files reside on the root filesystem, but a clean reinstall of the OS removes them. For long-term deployments, fold the commands into the /etc/rc.local legacy startup file or a systemd-tmpfiles rule:

sudo tee /etc/tmpfiles.d/logo-sysconfig.conf <<'EOF'
# Type Path                                      Mode User Group Age Argument
f    /etc/sysconfig/network/ifcfg-eth0           0644 root root -
f    /etc/sysconfig/network/ifcfg-wlan0          0644 root root -
d    /etc/sysconfig/network                      0755 root root -
EOF
sudo systemd-tmpfiles --create

7. Fix 3: Java Runtime Environment Configuration

This fix addresses root cause 3.3 and is documented by Siemens in Support Entry 25447431.

7.1 Confirm the Currently Active JRE

java -version
which java
update-alternatives --list java 2>/dev/null || true

If the version string is anything other than 11.0.13.x from Amazon Corretto, proceed with the steps below.

7.2 Install Amazon Corretto 11.0.13.8.1

1. Download the Debian package from the Amazon Corretto 11 distribution (x64, .deb).
2. Install and select it as the system default:

   sudo apt install -y ./corretto-11.0.13.8.1-linux-x64.deb
   sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-11-amazon-corretto/bin/java 2000
   sudo update-alternatives --set java /usr/lib/jvm/java-11-amazon-corretto/bin/java
   java -version

3. Remove any other JDK/JRE so the LSC launcher does not pick the wrong runtime:

   sudo apt remove -y openjdk-11-jre openjdk-11-jdk openjdk-17-jre openjdk-17-jdk 2>/dev/null || true
   sudo apt autoremove -y

7.3 Set JAVA_HOME for the LSC User

LSC V8.x on Linux honors the JAVA_HOME environment variable when present. Pin it to the Corretto install:

cat >> ~/.bashrc <<'EOF'
export JAVA_HOME=/usr/lib/jvm/java-11-amazon-corretto
export PATH=$JAVA_HOME/bin:$PATH
EOF
. ~/.bashrc

7.4 Confirm LSC Launches Under Corretto

/opt/Siemens/LOGOComfort/logoComfort -version 2>&1 | head -n 3

The startup banner should report OpenJDK 64-Bit Server VM (11.0.13.8.1+9-LTS) or equivalent Corretto build.

8. Static IP Configuration for LOGO! 0BA8

The LOGO! 0BA8 IP must be set on the device itself (not via DHCP) and must match the subnet of the Linux PC. The factory default is 192.168.1.251 / 255.255.255.0.

8.1 Configure the LOGO! 0BA8 IP from the Front Panel

1. On the LOGO! 0BA8, press ESC to enter the main menu.
2. Navigate to Network and select IP Address.
3. Enter 192.168.1.251 and confirm.
4. Enter the subnet mask 255.255.255.0 and confirm.
5. Set the gateway to 0.0.0.0 (or to the router IP if the LOGO! must reach an HMI outside the subnet).

8.2 Configure the PC Ethernet with Netplan (Ubuntu 22.04+)

sudo tee /etc/netplan/01-logo.yaml <<'EOF'
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      addresses:
        - 192.168.1.56/24
      routes:
        - to: 0.0.0.0/0
          via: 192.168.1.1
          metric: 100
EOF
sudo netplan apply

8.3 Configure the PC Ethernet with NetworkManager (Linux Mint 22.3)

nmcli con add type ethernet ifname eth0 con-name logo-eth \
    ipv4.addresses 192.168.1.56/24 \
    ipv4.gateway 192.168.1.1 \
    ipv4.method manual
nmcli con up logo-eth

9. LSC Version Compatibility Matrix

10. Step-by-Step Recovery Procedure

Apply the three fixes in the order that has the highest field success rate. Stop after the first successful transfer; do not skip a fix that is not strictly needed.

1. Power-cycle the LOGO! 0BA8 to clear any pending transfer state. Wait 10 seconds with power removed, then re-apply power.
2. Disable WiFi on the Linux PC (Fix 1, Section 5).
3. Apply the sysconfig fix (Fix 2, Section 6).
4. Install Amazon Corretto 11.0.13.8.1 and remove other JREs (Fix 3, Section 7).
5. Confirm the IP configuration on both ends (Section 8).
6. Launch LOGO!Soft Comfort from a fresh shell so the JAVA_HOME change is picked up:

   bash -lc '/opt/Siemens/LOGOComfort/logoComfort &'

7. Open the project and select Tools → Transfer → PC → LOGO! (or F5).
8. Select the LOGO! 0BA8 in the network dialog. The discovered device should report firmware 0BA8.Standard and IP 192.168.1.251.
9. Click Transfer and monitor the progress dialog.
10. Verify on the LOGO! front panel: the program name and date/time should match the project.

11. Verification and Acceptance Test

A successful transfer must satisfy all of the following acceptance checks. If any check fails, return to Section 10 and re-apply the corresponding fix.

12. Troubleshooting Matrix

13. Quick Command Summary

For an experienced engineer who already understands the three root causes, the canonical fix sequence is:

# 1. WiFi off
sudo nmcli radio wifi off
sudo ip link set wlan0 down

# 2. Sysconfig skeleton
sudo mkdir -p /etc/sysconfig/network
sudo touch /etc/sysconfig/network/ifcfg-eth0
sudo touch /etc/sysconfig/network/ifcfg-wlan0

# 3. JRE (Amazon Corretto 11.0.13.8.1)
sudo apt install -y ./corretto-11.0.13.8.1-linux-x64.deb
sudo update-alternatives --set java /usr/lib/jvm/java-11-amazon-corretto/bin/java
export JAVA_HOME=/usr/lib/jvm/java-11-amazon-corretto

# 4. Static IP on PC
sudo ip addr add 192.168.1.56/24 dev eth0
sudo ip link set eth0 up

# 5. Launch LSC
/opt/Siemens/LOGOComfort/logoComfort &