TP1200 Comfort Start Center Missing: OS Update Recovery Guide

Problem Overview

Field reports for the SIMATIC HMI TP1200 Comfort (catalog number 6AV2124-0MC01-0AX0 and related variants) describe a recurring failure mode in which, after a Siemens-recommended operating system (OS) update combined with a factory reset, the panel no longer displays the Start Center on reboot and the configured HMI project fails to auto-start. Operators observe a black or empty screen, the desktop never appears, and the panel can no longer be used to load or transfer a project. Because the device is reachable on the network (the MAC address remains visible to TIA Portal / Proneta) the panel is not electrically dead, but from a functional standpoint it behaves as a "brick" until the runtime environment is restored.

The same symptom has been reported on the related TP1500 Comfort, TP700 Comfort, TP900 Comfort, and the KP/TP Comfort 4-inch variants. Siemens addresses the recovery in entry ID 19701610 — "How do you do an operating system update on operator panels or perform a reset to factory settings?" — but the published procedure does not, by itself, guarantee success on every device that has previously been upgraded across multiple TIA Portal major versions (e.g., V13 → V16).

Affected Hardware, Firmware, and Software Matrix

Root Cause Analysis

Three distinct root causes have been confirmed on TP1200 Comfort panels exhibiting the missing-Start-Center symptom:

1. Corrupted runtime image after a partial OS update. ProSave pushes a new firmware .ime, the panel reboots into a transient loader, and either the write to internal flash aborts (e.g., loss of power, watchdog reset, or a USB stick pulled early), or the loader exits before the registry hive is rebuilt. The result is a flash partition that still contains the previous HmiRTm.exe and pdata.fwc from an older TIA Portal major version, but the Start Center shell and associated control panel applet binaries from the new image are missing. The user can browse the \Flash\Simatic\ directory over a network share because that partition is intact; the runtime, however, cannot find the Start Center DLL chain and the application never launches.
2. Incompatible firmware / project major-version mismatch. A panel originally commissioned with TIA Portal V13 has its image, registry, and project file all keyed to the V13 runtime signature. Performing an OS update to a V16 firmware while the project on the panel is still a V13 .fwc produces a non-bootable hybrid: the V16 loader loads, the V13 pdata.fwc is rejected by the new runtime, and the Start Center is bypassed. The panel drops to a black screen with only the network stack up.
3. Factory reset that wipes the recovery image pointer. The Comfort panel maintains a hidden restore partition used by the OS Update wizard's "Reset to factory settings" checkbox. If that partition is itself overwritten by a bad .ime (firmware newer than the recovery image was built for), the next "restore" loads a partial image and the Start Center is not regenerated.

Pre-Recovery Diagnostics

Before committing to a full OS update, gather the following so the recovery is targeted, not blind:

1. Confirm network reachability. From a PC on the same subnet, ping the panel's configured IP. The TP1200 Comfort defaults to DHCP with a fallback address scheme when ProSave has been used at least once. Use arp -a to read the MAC if the IP is unknown — visible MAC proves the NIC, bootloader, and base Win32 subsystem are alive.
2. Inventory the existing flash content. If the panel still allows a network share (\\flash), enumerate \Flash\Simatic\, \Flash\Automation\, and the System\ directories. The presence of HmiRTm.exe but absence of Start Center.exe (or the absence of SimaticShell.dll) is diagnostic of a partial image.
3. Capture the current firmware version. Connect with TIA Portal "Online > Accessible devices" or with ProSave > "Read from device". Note the panel order number (6AV2124-0MC01-0AX0), the firmware build string, and the TIA Portal version that last compiled the project. This avoids re-installing the same broken image.
4. Test the boot delay. In Control Panel > Transfer Settings > Directories, the "wait time" parameter (typically 0–30 s) controls how long the Start Center stays on screen before auto-starting pdata.fwc. A wait time of 0 with a corrupted auto-start entry makes the panel appear to go straight to a black screen, which is visually identical to a missing Start Center. Confirm the value before assuming the runtime is dead.
5. Check the SD / system card slot. The TP1200 Comfort has a slot for SIMATIC HMI memory cards. A card with a stale pdata.fwc can override internal flash and cause the symptoms even after a successful internal-flash update. Eject the card before further work.

Recovery Method 1 — Official Siemens OS Update and Factory Reset

Follow entry ID 19701610 exactly. The two variants are:

1. OS Update only (preserves project): Open ProSave, select the panel order number, choose "Operating system update", check "Reset to factory settings" only if the project itself is suspected of corruption. Browse to the firmware image from the TIA Portal installation or the Siemens support download (file pattern *.ime or *.fwc delivered with WinCC Comfort / TIA Portal under Support > Images). The transfer is signed by Siemens — do not edit the image or use a third-party resaved copy.
2. OS Update + Reset to factory settings (clean slate): Tick the "Reset to factory settings" box. The panel will boot into a minimal loader, write the new image to internal flash, then automatically reboot a second time into the freshly installed Start Center. The pdata.fwc from the project is removed; the project must be re-transferred afterward.

Recovery Method 2 — Force a Clean Image via Bootloader Service Mode

If Method 1 leaves the panel still missing the Start Center, force the bootloader to do a low-level re-image. This procedure is documented in the device manual and uses the service menu that ProSave triggers when the operating system on the panel is unbootable.

1. Power off the panel. Hold down the Service button on the back of the TP1200 Comfort (a recessed tactile switch; use a non-conductive tool) while applying power. The device enters Service mode; the touch remains dark and the bootloader listens on all configured PROFINET / Ethernet interfaces.
2. On the engineering PC, run ProSave with the panel order number 6AV2124-0MC01-0AX0 selected. Set the connection to Ethernet and the IP to the service-mode address 192.168.0.1 / mask 255.255.255.0 (the panel's default in service mode, regardless of prior project settings). The panel will respond even when no Start Center is running.
3. Choose Operating system update > Reset to factory settings > browse to the matching *.ime. The transfer is at the bootloader level — it bypasses Win32 entirely and writes the image directly to the active flash partition plus the recovery partition.
4. When the transfer reports success, the panel reboots automatically. Expect two reboots: the first writes the loader chain, the second brings up the freshly installed Start Center. Allow 5–10 minutes; the panel can appear unresponsive for the first 2–3 minutes of the second boot while the registry hive is rebuilt.

Recovery Method 3 — USB / SD Card Image Restore

When the panel is unreachable over Ethernet (rare, but seen when the bootloader is itself corrupted), use the external storage restore path:

1. On a Windows PC, write the official *.ime to the root of a FAT32-formatted USB stick. Do not place the file in a subfolder; the bootloader scans the root only.
2. Insert the USB stick in the rear USB port of the TP1200 Comfort. Power-cycle the device while the stick is inserted. The bootloader detects the file, prompts on a connected external monitor (the TP1200 has no display output for service mode, so this step is largely silent), and re-images internal flash.
3. When the LED pattern returns to steady (no flashing), remove the USB stick and power-cycle again. The panel should boot into the Start Center.

If the panel is fitted with a SIMATIC HMI system card, the same image can be deployed from the card; the card slot is preferred over USB because the bootloader can read SDXC faster and validate the signature before writing.

Recovery Method 4 — TIA Portal Project Re-Transfer with Correct Major Version

Once the Start Center is back, the project must be recompiled in the TIA Portal major version that matches the firmware on the panel:

1. In TIA Portal, open the project. Right-click the HMI device and select Change device / version. Confirm the device version is 6AV2124-0MC01-0AX0 with a firmware major version that matches the runtime you just installed.
2. Recompile, then transfer the project via ProSave or TIA's Online > Compile and download to device. Watch the transfer log: a successful transfer ends with "Transfer completed successfully" and a non-zero number of bytes; failure to compile for a target firmware major version will surface as "Device version mismatch".
3. Set Control Panel > Transfer Settings > Auto Start to Enabled and Wait time to a value between 0 and 30 s as required by the application. Save, then reboot to confirm the project auto-starts from \Flash\Simatic\<project>\pdata.fwc.

Verification

Troubleshooting Matrix

Field-Proven Caveats

• Never interrupt an OS update once the panel has rebooted into the loader. A power loss at that moment is the most common cause of a real brick where the bootloader itself is corrupted; recovery then requires the USB/SD method and the correct signed IME.
• Always remove any SD / system card before an OS update. A card with a stale pdata.fwc can override the freshly installed internal image and make it look as if the update failed.
• When upgrading across TIA Portal major versions (V13 → V14 → V15 → V16 → V17), do one major-version step at a time, performing a full OS update with factory reset at each step. Skipping steps is the leading cause of the missing-Start-Center symptom reported in field service tickets.
• Keep the engineering PC's ProSave version aligned with the TIA Portal version. ProSave older than the TIA major version cannot push the corresponding firmware image; the transfer aborts silently and the panel boots into the previous (broken) image.
• Document the firmware build string after every successful update. The image files are signed per firmware major; the same physical IME re-installed on a different panel can be rejected if the panel's hardware revision has changed.

References Inside This Guide

• Siemens Support Entry ID 19701610 — official OS update / factory reset procedure for SIMATIC HMI Operator Panels.
• SIMATIC HMI TP1200 Comfort product support page — firmware downloads, manuals, FAQs for catalog number 6AV2124-0MC01-0AX0.