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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

F125

Flash Update Req

Allen-Bradley · PowerFlex 520-series Adjustable Frequency

What does F125 mean?

The firmware residing in the drive's flash memory is corrupt, mismatched, or incompatible with the current hardware configuration. This prevents the drive from initializing or operating correctly, indicating that the drive's operating system needs to be reinstalled or updated.

Common Causes

  • Firmware update process was interrupted or failed due to power loss or communication timeout.
  • Incorrect firmware version loaded that is incompatible with the specific drive hardware revision (e.g., 20G firmware on a 20A drive).
  • Corruption of the drive's flash memory due to electrical noise (EMI) or transient voltage spikes on the control power input.
  • Internal hardware defect in the flash memory module preventing proper write and read operations.
  • Attempted downgrade of firmware to a version incompatible with the existing bootloader.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Connect to the drive's programming port (e.g., USB or Ethernet) and confirm communication using the manufacturer's software utility (e.g., Studio 5000 Logix Designer).

  2. 2

    Verify the exact drive catalog number and hardware revision (found on the nameplate) to determine the correct firmware version required.

  3. 3

    Perform a controlled firmware update using the manufacturer's recommended flashing tool, ensuring stable 24VDC control power (e.g., measured at terminal TB1) throughout the entire process.

  4. 4

    After the firmware update completes, cycle the 24VDC control power and monitor the drive's status indicators for successful initialization.

  5. 5

    If the fault persists, attempt a full factory reset (e.g., set Parameter P0-01 to 0 and save) before re-attempting the firmware flash.

Browse all codes in this manual (48)
Verified technical data. Last updated: April 2026

Related Faults

F000No FaultF002Auxiliary InputF003Power Loss
Source: Allen-Bradley PowerFlex 520-series Adjustable Frequency
View Official PDFSearch more codes in this manual