S7-1200 CPU Firmware Upgrade V1.x to V2.x via SIMATIC Card

Problem Overview: TIA Portal V15 Incompatibility with S7-1200 V1.0.1

A CPU 1212C running firmware V1.0.1 cannot establish an online connection with TIA Portal V15 (or any TIA version V13 SP1 and newer). The Engineering Tool reports an Incompatible firmware version or Online: Cannot reach the partner error during the "Go online" sequence, even when the Ethernet link is healthy and the IP address is reachable. The root cause is a strict version matrix between the S7-1200 CPU firmware release and the TIA Portal engineering release: TIA V15 was built to communicate with V4.x firmware generation CPUs. V1.x firmware requires TIA V11 SP2 / V12 SP1.

Two corrective paths exist:

1. Tool-side fix: Install the TIA Portal version that matches the existing CPU firmware (TIA V11 SP2 for V1.x, TIA V13 SP1 for V2.x, TIA V14 SP1 for V3.x, TIA V15 for V4.x).
2. CPU-side fix: Upgrade the CPU firmware from V1.x to V2.x via SIMATIC memory card, then continue with a current TIA release.

Firmware Version Compatibility Matrix

Prerequisites

• CPU: SIMATIC S7-1200 CPU 1212C (6ES7212-1A/B/HExx-0XB0 series, V1.x hardware). Confirm the firmware version via Online > Accessible devices with TIA V11 SP2 before attempting any upgrade.
• SIMATIC Memory Card (SMC): Siemens Article No. 6ES7954-8LE03-0AA0 (2 MB, empty) or 6ES7954-8LF03-0AA0 (4 MB). The card must be empty or freshly formatted in TIA Portal (Card Reader/USB).
• Firmware file: Download the S7-1200 V2.x firmware update package that matches the exact Article No. of the target CPU. For CPU 1212C DC/DC/DC, the file is named S71200_CPU1212C_V2.x.x.zip from the Siemens Industry Online Support (SIOS) entry Firmware update S7-1200 CPU.
• 24 V DC load power supply (for DC/DC/DC variants) or 120/230 V AC (for AC/DC/RLY variants) capable of holding output during the upgrade. A brownout during the firmware transfer bricks the card slot operation; the CPU will still run, but the upgrade must be restarted.
• TIA Portal V11 SP2 or V13 SP1 (the older tool is still required to write the firmware file onto the SMC, because V15 does not support V1.x/V2.x CPU project files). WinCC V11 SP2 is needed if the project also contains Comfort/ Basic Panels.
• Programming device or PC with Ethernet interface, Windows 7 SP1 / Windows 10, and a card reader compatible with the SMC form factor.

CPU Hardware vs. Firmware Revision Mapping

The Article No. of the S7-1200 CPU encodes both the hardware release (FS: Functional State) and the firmware generation that originally shipped on the device. The last three characters of the order number (the -0XB0 suffix) indicate compatibility:

Step-by-Step Firmware Upgrade via SIMATIC Memory Card

1. Power down the CPU. Remove the terminal block connector or switch off the PS. The CPU must be in STOP or power-off state to accept a new firmware image.
2. Insert the SIMATIC Memory Card into the PC card reader slot. Confirm Windows reports the device as Removable Disk.
3. Open TIA Portal V11 SP2 / V13 SP1 (the older release is required to enumerate the V1.x project environment). Navigate to Project > Card Reader/USB > Properties of the SMC.
4. Format the SMC with the "Format" button. Tick Reset to factory settings. This erases any program, archive, or recipe data stored on the card.
5. Place the firmware update file on the card root. The firmware ZIP must be unpacked. The S7-1200 boot loader looks for a specific file naming convention: FWUPDATE.S7S at the root of the SMC. Some Siemens firmware packages ship with this file already prepared; otherwise use the "Firmware Update" button inside TIA's Card Reader view to generate it.
6. Eject the SMC safely from Windows. Remove the card from the reader.
7. Insert the SMC into the CPU's card slot (push the card in until the ejector protrudes; the CPU does not need power for insertion, but the firmware loader triggers only at startup).
8. Power up the CPU. Observe the MAINT LED blinking yellow and the RUN/STOP LED blinking yellow. The CPU reads the FWUPDATE.S7S file and writes the new firmware to internal flash. This takes 30 – 90 seconds depending on image size.
9. Wait for the RUN/STOP LED to flash slowly green (firmware loaded) or to revert to a fault pattern (firmware rejected). The MAINT LED goes off on success.
10. Power down, remove the SMC. The SMC is now empty and can be reused for program transfer.
11. Power up again and confirm with TIA V11 SP2 / V13 SP1 Online > Accessible devices that the firmware field reports V2.0.x or higher.

Alternative: Matching TIA Portal Version to Existing V1.x Firmware

If the V1.x project must remain untouched (e.g., legacy machine, validated system), install TIA V11 SP2 instead of upgrading the CPU. The Engineering Tool family and the runtime project version must match the CPU firmware generation:

• STEP 7 Basic V11 SP2 — programming and commissioning S7-1200 CPUs only (firmware V1.x and V2.x).
• STEP 7 Professional V11 SP2 — adds S7-300/400/WinAC support on top of S7-1200 functionality.
• WinCC V11 SP2 (Basic / Comfort / Advanced / Professional) — required to edit HMI panels. Without the WinCC component, the Add new device wizard does not display the HMI option, which is the symptom reported when only the STEP 7 portion is installed.

Two official Siemens download paths are used in sequence:

1. First install SIMATIC STEP 7 V11 SP2 to obtain the project environment and online interface for the V1.x CPU.
2. Then install SIMATIC WinCC V11 SP2 (or the SP2 update on top of an existing V11 install) to enable HMI device objects inside the project tree. WinCC V11 SP2 is available as a 21-day trial license from the Siemens Industry Online Support entry 103499074 and the SP2 update pack from entry 56897511. WinCC engineering version mapping is documented in entry 99684510.

Engineering Tool Selection: STEP 7 Basic vs. Professional

For a CPU 1212C V1.0.1 with HMI panels, the minimum footprint is STEP 7 Basic V11 SP2 + WinCC V11 SP2 (Basic or Comfort, depending on the panel family). STEP 7 Professional is required only when the plant also contains S7-300/400 stations.

WinCC in TIA Portal for HMI Integration

WinCC for TIA Portal is shipped in four ascending editions, each unlocking a different panel class:

• WinCC Basic — KTP / KTP1000 / Basic Panels (4", 6", 10", 15") with monochrome or 256-color displays.
• WinCC Comfort — Comfort Panels (4" – 22"), TP177 successor line, full vector graphics, archive/recipe support, ProSave functionality.
• WinCC Advanced — adds PC Runtime (WinCC Runtime Advanced) and runs on a Windows host with SoftPLC capability.
• WinCC Professional — distributed SCADA, redundancy, plant intelligence, integrated into STEP 7 Professional V11 SP2 and newer.

The TIA Portal version (V11, V13, V15, V17, V19) is shared across STEP 7 and WinCC — the WinCC Service Pack level must match the STEP 7 level exactly. Mixing V13 STEP 7 with V11 WinCC leads to a project-revision mismatch error during device insertion.

Verification Procedure

1. Read the diagnostic buffer via TIA Online > Online & diagnostics > Diagnostics buffer. The buffer should contain the entry Firmware update successful with the new firmware version and the timestamp of the last power-up.
2. Inspect the online device with Online > Accessible devices. Confirm the firmware field reports the expected V2.x number, and the article number matches the CPU label.
3. Download a test program (a single "M0.0 = TRUE" block) to the CPU. Verify the green RUN LED stays solid and STOP->RUN transition is clean.
4. Cross-check the project version: TIA V13 SP1 must be installed to open a V2.x project offline; TIA V15 will refuse a V2.x project file with error The project cannot be opened because it was created with a newer/older TIA Portal version.
5. Cycle power twice to ensure the firmware survives a non-volatile storage test. The CPU should boot to the same firmware version each time.

Troubleshooting Matrix

SVG: Firmware Upgrade Decision Flow

Hardware Replacement Path (When Firmware Cannot Be Upgraded)

If the application requires TIA V15 / V16 / V17 features (SCL 1500-style syntax, OPC UA server, secure communication, motion control of S7-1200 with V4.x firmware), the V1.x CPU must be replaced. Compatible successors:

Engineering Tip: TIA Project Versioning Discipline

Mixing TIA versions inside one project is the most common cause of "impossible" online errors. Adopt these rules:

• Lock the project's TIA version at project creation time. Do not auto-upgrade.
• Use a parallel TIA install (V11 SP2 on a different PC) when an old project must remain V11.
• Archive the project as .ap11 / .ap12 / .ap13 / .ap15 matching the TIA version; do not use .zap15 for a V11 project — TIA V15 will silently upgrade it.
• Tag the SMC physically (label printer) with the firmware version and project version. This eliminates the "which firmware is on the card" question during commissioning.