Resolving Siemens IPC427E CPU 1507S Wrong Boot Option Error

1. Problem Overview

The SIMATIC IPC427E (article number 6AG4141-5BG47-0FA8) is a compact industrial PC that can be ordered preconfigured with the SIMATIC S7-1500 Software Controller (CPU 1507S F, order code 6ES7672-7FC01-0YG0). When the Software Controller boot loader is not properly installed, the virtual display of the CPU shows two consecutive status messages during the boot sequence:

1. "Connecting..." – the CPU virtual display attempts to bind to the IPC partition that contains the WinAC slot runtime.
2. "Wrong boot option" – the Software Controller boot manager cannot locate a valid Windows + Software Controller boot entry on the mass storage device.

Once the second message is displayed, TIA Portal cannot load any project to the virtual CPU because no PLC instance is initialized. The Windows host remains fully functional, but the automation layer is unreachable. The condition is documented across Siemens support attachments for the CPU 1505SP/1507S/1508S family and is independent of the CPU firmware version installed (confirmed against the V21.8, V30.0, and V31.1 manuals).

2. Affected Components and Versions

3. Symptoms and Diagnostic Sequence

The failure presents a deterministic, repeatable pattern. Use the table below as a diagnostic matrix to confirm the failure mode before attempting any remediation.

Field case data indicates that the Windows boot process itself may appear sluggish with a long "Getting Windows ready — Don't turn off your computer" screen on the blue Windows boot loader. This is a separate symptom that points to a corrupted BCD or an ESP/EFI partition problem, and it is one of the earliest indicators that the disk layout is wrong.

4. Root Cause Analysis

The Software Controller requires a custom boot configuration on the IPC mass storage device. When the IPC is delivered with the Software Controller pre-installed, Siemens ships a disk image that contains:

1. A GPT partition table with a 100 MB EFI System Partition (ESP).
2. A Windows Recovery partition.
3. A Windows primary partition containing the operating system.
4. A second Software Controller partition (or extended entry) that hosts the WinLC runtime.
5. The Siemens boot menu integrated into the Windows Boot Manager. This menu must show two entries: Windows and Windows + Software Controller.

If any of the following conditions is true, the CPU virtual display transitions from Connecting... to Wrong boot option:

• The disk has been converted from GPT to MBR (e.g. by a Windows 7 imaging tool or by legacy Linux partitioning).
• The EFI System Partition has been deleted, formatted, or overwritten.
• The Windows Boot Manager entry \EFI\Microsoft\Boot\Bootmgfw.efi has been replaced or relocated.
• The Siemens boot menu hook in \EFI\Siemens\Boot\Bootx64.efi is missing.
• BIOS boot mode is set to Legacy only while the disk uses a GPT header (or vice-versa).
• The Visual C++ 2015–2019 Redistributable x64 prerequisite of the Software Controller failed to install (manifested as a warning, not a fatal error, during the repair setup).
• A foreign driver or runtime, notably Intel® Rapid Storage Technology (RST) in non-AHCI mode, conflicts with the WinLC disk access layer.

5. Pre-Installation BIOS Configuration

Before any Software Controller installation or repair attempt, enter the BIOS of the IPC427E (press <ESC> immediately after power-on to reach the boot menu, then select Setup or press <F2> depending on firmware revision). Apply the following settings:

1. Set Boot Mode to UEFI (preferred) or Both (UEFI + Legacy). Do not select Legacy Only if the disk uses GPT.
2. Disable Secure Boot only if the Siemens recovery image fails to boot with it enabled. Secure Boot is supported by Siemens factory images; preserve it whenever possible.
3. Confirm that the EFI boot order lists the primary mass storage device first.
4. Verify that the disk controller is set to AHCI (not RAID or Intel RST Optane mode).
5. Save and exit. Power-cycle the IPC and re-enter the boot menu with <ESC>.

6. Required Disk Partition Layout

The Software Controller requires a specific partition layout. The following table summarizes the GPT layout that Siemens installs at the factory:

To verify the current layout from Windows, open an administrative command prompt and execute:

diskpart
list disk
select disk 0
list partition

Confirm that Disk ### shows a * in the GPT column. If the disk shows no asterisk, the partition style is MBR and the Software Controller boot path will fail.

7. Recovery Procedure — Full Reinstall

When the boot partition or the GPT header is damaged beyond the reach of a repair setup, perform a clean reinstall using the Siemens recovery media.

1. Obtain the official Siemens recovery USB stick or build one from the recovery ISO shipped with the IPC.
2. Connect a USB keyboard to the IPC and power on.
3. Press <ESC> during POST and select the USB device from the Boot Menu.
4. Boot into the Windows Recovery Environment and select Install Windows.
5. On the partition selection screen, delete every existing partition on the target disk (warning: all data on the disk is erased). This step is essential to remove a corrupt MBR header that the recovery installer might otherwise reuse.
6. Allow the recovery installer to recreate the GPT partitions automatically. Do not interrupt the formatting stage.
7. Complete the out-of-box experience (OOBE) with the locale and computer name of your choice. Activate Windows with the OEM key embedded in the firmware.
8. Install all Windows updates from Windows Update, including the cumulative updates through the latest LTSB/LTSC rollup.
9. Verify the partition layout with diskpart as described in section 6.

8. Software Controller Installation

With a clean, correctly-partitioned Windows installation, install the Software Controller in the order specified by Siemens.

1. Insert the TIA Portal installation medium or run the Siemens Automation License Manager setup.
2. Launch Setup.exe of the Software Controller (CPU 1507S F) and follow the dialogs.
3. Accept the license agreement and select the installation path (default C:\Program Files\Siemens\Automation\WinLC).
4. When prompted, install the Visual C++ 2015–2019 Redistributable (x64). This prerequisite is bundled with the Software Controller installer; if it fails, install it manually from the Microsoft redistributable package and reboot.
5. Reboot the IPC when the installer requests it. The first reboot after the Software Controller install presents the Siemens boot menu with two entries:

• Windows — boots the IPC into Windows without starting the Software Controller.
• Windows + Software Controller — boots Windows and then automatically starts the WinLC virtual CPU.

6. Select Windows + Software Controller. The Windows logon screen appears, followed by the CPU virtual display. The status bar transitions from Connecting... to RUN (or STOP if no project is loaded).

9. Repair Installation Pitfalls

Selecting Repair in the Software Control Control Panel entry is often the first step technicians take when the boot menu disappears, but repair has known limitations on the IPC427E:

• Repair may not rewrite the EFI boot hook if the installer detects a previous, partially corrupted hook and decides to preserve it. In that case, a full reinstall of the Software Controller (uninstall → reboot → install) is required.
• The repair installer writes two VC++ Redistributable warnings to the log file. These are non-fatal but are routinely misread as installation errors. The log file is located at %TEMP%\SiemensInstall.log; search for the strings VC_REDIST and WRN_.
• Repair does not fix an MBR disk. If the disk is MBR, repair finishes successfully but the virtual display still shows Wrong boot option. Convert the disk to GPT using mbr2gpt /convert /disk:0 from the Windows Recovery Environment before repairing the Software Controller.

10. Driver and Runtime Conflicts

Several software components installed on the IPC can break the Software Controller boot path. Remove or disable each of the following before the Software Controller is installed:

11. Verification Procedure

After every recovery or repair action, run the following verification sequence. All steps must pass before the IPC is returned to production.

1. Boot menu verification. Reboot the IPC. Confirm that the Siemens boot menu appears with both Windows and Windows + Software Controller entries. If only one entry is present, the Software Controller boot hook is missing.
2. CPU virtual display verification. Select Windows + Software Controller. After Windows logon, confirm that the CPU virtual display transitions from Connecting... to RUN or STOP. The display is opened from the Start menu by launching SIMATIC S7-1500 CPU Display.
3. TIA Portal online connection. Open TIA Portal, navigate to Online → Accessible nodes, and confirm that the IPC appears as an X1/X2 network node. Right-click the CPU and select Online & diagnostics; the diagnostic buffer should be readable.
4. Project download test. Compile a minimal project (one tag, one OB1) and download it to the virtual CPU. Verify that the download completes without error and that the CPU enters RUN.
5. Persistent reboot test. Reboot the IPC three times. Each reboot must end in the CPU virtual display reaching RUN or STOP within 60 seconds. If the boot hangs at Connecting... for longer than 90 seconds, repeat the recovery procedure.
6. Diagnostic buffer inspection. In TIA Portal, open Online & diagnostics → Diagnostics buffer. Confirm that no entry references BOOT_ERROR, WRONG_BOOT_OPTION, or WINLC_BIND_FAILED.

12. Field-Validated Root Cause Summary

The historical record for this failure across multiple Siemens support threads converges on the following matrix. The matrix can be used as a fast triage tool in the field:

13. Preventive Measures

To prevent a recurrence of the Wrong boot option condition:

• Document the partition layout (GPT, ESP size, recovery partition) on every IPC427E in service and store it with the asset record.
• Disable Windows automatic disk optimization on the EFI System Partition.
• Block installation of Intel RST and other storage filter drivers via Group Policy or a provisioning script.
• Standardize on the Siemens recovery image as the only imaging source. Avoid Linux-based imaging tools (Clonezilla in legacy mode, dd) on the IPC427E.
• Apply the latest cumulative updates for Windows 10 LTSB and the latest CPU 1507S firmware distributed with TIA Portal before commissioning. Reference the latest CPU 1505SP/1507S/1508S manual for firmware-specific changes:

CPU 1505SP (F/T/TF), CPU 1507S (F), CPU 1508S (F/T/TF) V31.1 manual
CPU 1505SP/1507S/1508S V30.0 manual
CPU 1505SP/1507S/1508S V21.8 manual

14. Related Considerations

If the IPC427E is part of a larger machine that runs WinCC Runtime Advanced or a third-party SCADA package, treat the Software Controller as the last component to be installed. The reason is that WinCC installers and many OPC UA stacks register port reservations and certificate authorities that are not always cleaned up on uninstall. A clean install in the order Windows → chipset drivers → TIA Portal → WinCC → Software Controller minimizes the risk of cross-package conflicts.

For environments with managed updates (e.g. WSUS, SCCM, or a Siemens SIMATIC Automation Tool rollout), exclude the EFI System Partition from any scheduled defragmentation and exclude the Siemens boot hook from any BCD or boot loader rewrites. A successful managed update of Windows must not touch the Siemens boot entry.