Siemens MP377 'Image is Corrupt' Boot Error: Recovery Guide

Problem Overview

The Siemens SIMATIC MP 377 Multi Panel is a 15-inch HMI that runs Windows CE 5.0 or 6.0. When an OS update is interrupted — by a power loss, a dropped Ethernet connection, or a corrupted transfer file — the panel can no longer boot into its runtime image. Instead, the BootCE loader halts with the message ERROR: Image is corrupt! and falls through to Waitting for image update... The device is still alive on Ethernet, but the only way out of this state is a successful OS transfer from Siemens SIMATIC HMI tools.

This article documents a field case where a failed update on an MP 377 (BootCE Version 01.00.33.00, MAC 00-0e-8c-aa-d7-37) prevented both WinCC flexible and ProSave from completing a recovery on the original laptop. The root cause turned out to be a defective Ethernet port on the engineering station — not a damaged panel. The procedure below isolates the panel, the cable, and the PC NIC in the right order so the same time sink does not happen on the next service call.

Affected Hardware and Firmware

Document the panel and image state before touching any tool. The BootCE banner reveals the loader version, the MAC address, and the corruption point. Capture the exact text of the error so it can be matched against Siemens KB entries.

Symptom Analysis: Reading the BootCE Banner

BootCE is a small Windows CE loader stored in a protected region of the internal flash. Its only job is to validate the main OS image and then hand control over to it. When the validation fails, the banner tells you exactly where in the chain the failure happened:

1. Enabling update mode... — BootCE has set the panel to transfer mode. From this point on, the panel accepts an image only via the Ethernet port and will not start the runtime.
2. Loading image from flash... — The loader is reading the main OS region of the NAND flash. If the read itself fails (bad block, ECC error) you will see hardware-level errors; if the read succeeds but the checksum does not match, you get Image is corrupt!.
3. ERROR: Image is corrupt! — The signature on the stored image does not match the loader's expectation. The most common cause is an interrupted previous OS update, where the new image was partially written and the old one was already erased.
4. Waitting for image update... — The loader has given up booting and is now acting as a TFTP-style target. ProSave or WinCC flexible can push a new image to it.

If the screen is frozen before this banner, the bootloader itself was damaged. That is a factory RMA case; the field procedures below will not bring it back.

Root Cause Investigation

Three layers can cause a stubborn recovery: the panel, the network, or the engineering workstation. Test them in that order, because the panel is the most expensive to misdiagnose.

In the documented case, the panel responded with the expected Image is corrupt! banner, the cable was known good, and the laptop's integrated Ethernet port had an intermittent physical fault that was invisible to Windows. The fix was to switch to a known-good PC. Engineering time was lost because the laptop could ping the panel from cached ARP, but transfers stalled at 0% inside ProSave.

Prerequisites for Recovery

Before you start the OS transfer, gather the items below. The Siemens OS update procedure in ProSave 1.2 manual (PDF) and the TIA Portal Update OS documentation both assume this baseline.

• The MP 377 image .img file matching the panel variant (e.g. MP377.img) from the Siemens HSP or from the WinCC flexible installation DVD.
• ProSave installed locally, version matched to the panel image. Mixed versions are the single biggest cause of mid-transfer aborts.
• A second Windows PC with a known-good Ethernet port, ideally with a USB-to-Ethernet adapter as a hot spare.
• A shielded CAT5e crossover cable for a direct connection, or a small unmanaged switch and two straight-through cables.
• Static IP configuration on the PC: address 192.168.0.100, mask 255.255.255.0, no gateway. The panel's BootCE default is 192.168.0.1 (visible in WinCC flexible under Transfer > Ethernet > IP Address in the project).
• Windows Firewall and any third-party AV disabled for the duration of the transfer.

Step-by-Step Recovery Procedure

1. Power the panel and confirm the BootCE banner. If the panel boots into CE normally, the corrupt-image state has cleared and you do not need a recovery transfer — investigate why instead. If the banner shows Waitting for image update..., proceed.
2. Connect the engineering PC directly to the panel. Use a crossover cable for a direct link, or a small switch with two patch leads. Do not chain through plant VLANs — multicast and broadcast filtering can prevent the transfer from completing.
3. Verify link and IP. Both link LEDs must be lit. On the PC, set a static IP in the same subnet as the panel (default 192.168.0.1). Ping the panel. A successful ping confirms L3 reachability.
4. Launch ProSave. On the General tab, set Device type to MP 377 15" Touch (or the matching variant), Connection to Ethernet, and enter the panel IP.
5. Open the OS Update tab. Browse to the .img file. Tick Reset to factory settings only if you want the panel to come back empty and re-load its project later; leave it unticked if you want to preserve a project that was already on the panel.
6. Click Update OS. ProSave will first establish a control channel, then push the image in blocks. Expect 8 to 25 minutes depending on image size and link speed. Do not interrupt.
7. Wait for the panel to reboot automatically. At the end of a clean transfer the panel will reboot twice: once to write the image, once to launch it. The CE desktop should appear within a few minutes.
8. Restore the project. Use WinCC flexible Transfer > Project > Restore or Download to push the project back onto the panel. Confirm the version number in the project header matches what is on the panel.

Network Troubleshooting Matrix

If ProSave fails to connect, fails during the transfer, or hangs at 0%, walk this matrix in order. Each step removes a layer of variables from the next attempt.

Verifying the Recovery

Successful recovery is not the same as a successful image transfer. The panel must also accept its project and stay running for at least one full duty cycle before the ticket is closed.

1. Confirm the CE desktop appears within 3 minutes of the second reboot.
2. In the Control Panel, open System > About and check the image version matches the .img that was loaded.
3. Open WinCC flexible and connect to the panel over Ethernet. The transfer dialog should report the panel's image and project versions.
4. Download the project (or restore from backup) and watch the runtime start. Touch all four corners of the screen to confirm calibration.
5. Leave the panel running for at least 30 minutes, including one process cycle, before signing off.

Field Engineering Notes

A few caveats that are easy to miss in the official documentation and that have cost service engineers hours in the field:

• The Reset to factory settings checkbox in ProSave erases the project and the option keys. If the panel has HMI option licenses (e.g. Sm@rtServer, OPC) installed, document and back them up first using Options > Backup in ProSave.
• The MP 377 BootCE IP is set by the project, not by the panel's startup configuration. If the project IP is unknown, you can use the panel's Service > IP Config page once the project is loaded — but not while the panel is in Waitting for image update... state.
• A USB-Ethernet adapter is a faster swap than diagnosing the built-in NIC, and the spare can be a labelled shop asset for the next call.
• If the panel was running TIA Portal's Update OS workflow, the source path is Online > HMI Device Maintenance > Update OS; the same TCP ports and IP rules apply.
• Always capture the BootCE banner with a phone photo before starting the recovery. If a second engineer is called in, the loader version narrows down which image set is required.

Prevention and Good Practice

The cheapest fix for this fault is the one that never lets it happen.

• Use a UPS on the engineering station and on the panel during any OS update.
• Take a full ProSave backup (Backup > Complete backup with recipes and passwords) before every update. The backup file is the fastest path back to a working panel if the new image fails.
• Match ProSave version to the image version. Siemens publishes a compatibility matrix; mixed versions are the most common source of mid-transfer aborts.
• Verify the .img SHA-256 against the value Siemens publishes in the HSP readme before starting the transfer.
• Document the engineering station's Ethernet port in the panel's maintenance record. If a recovery ever needs to happen in a hurry, the working PC is already known.

When to Escalate

Escalate to Siemens support through the official SIOS channel if any of the following are true after the matrix above has been worked through:

• The panel never reaches the BootCE banner after a power cycle.
• Two different .img files, from two different PCs, both fail at the same percentage.
• The panel reports a different MAC prefix than 00-0e-8c, which indicates the unit has been re-labelled or the flash has been overwritten with non-Siemens firmware.
• The panel is still under warranty and shows symptoms of NAND wear (slow boot, sporadic read errors, recurring Image is corrupt!).