Error Code CC164 indicates a ROM contents error (MSC) on Konica Minolta bizhub machines. The abbreviation “MSC” refers to the Memory/Sensor Control board (also called the MSC board or Image Processing board depending on the model). This error occurs when the machine performs a checksum verification on the firmware stored in the MSC board’s ROM (or flash memory) and detects that the data does not match the expected values.

The machine is telling you that the program or configuration data on the MSC board is corrupted — either because of a failed firmware update, a defective memory chip, or an electrical event that altered the ROM contents. Without valid firmware, the MSC board cannot control the image processing pipeline (scanner, laser, and print image data), so the machine halts operation and displays CC164.

Overview Table

All Affected Models and Exact Component References

Error CC164 is documented across many Konica Minolta bizhub models that use a separate MSC board for image processing. The board name, ROM location, and firmware update procedure differ between model families. Using the correct references for your model is critical.

Note: On newer i‑series models (C450i, C550i, etc.), the MSC function is integrated into the BASEB, and a CC164 error may instead indicate a BASEB firmware corruption. Always verify with your service manual.

What Does Error Code CC164 Mean?

The MSC board (Memory/Sensor Control board) is responsible for critical real‑time image processing: reading the CCD sensor (scanner), controlling the laser diodes (print head), and applying gamma correction, screening, and color conversion. Its firmware is stored in a NOR or NAND flash ROM.

During each power‑on self‑test, the MFPB or PRCB instructs the MSC board to compute a checksum over its entire firmware region. This checksum is compared to a stored value. If they do not match, the machine concludes that the ROM contents are corrupted and displays CC164.

CC164 fires when the MSC board’s firmware checksum fails. The machine cannot trust that the image processing algorithms are correct, so it refuses to boot.

Three Failure Scenarios

• Scenario A — Corrupted firmware due to failed update (most common ~60%): A firmware update was interrupted (power loss, USB removal too early, network timeout) before the MSC section completed. The partial firmware causes a checksum error.
• Scenario B — Physical flash memory defect (~30%): The flash chip itself has a bad sector, has exceeded its write/erase cycles, or suffers from bit rot. This requires replacement of the MSC board (or, on integrated models, the MFPB/BASEB).
• Scenario C — Electrical damage or ESD event (~10%): A voltage spike on the board corrupted the firmware or damaged the memory controller. This is more common in environments with poor grounding.

Step 1 — Attempt Firmware Recovery Using USB (First and Most Important)

Before replacing any hardware, you must attempt to rewrite the MSC firmware. The machine often has a recovery mode that allows firmware re‑installation even when CC164 is displayed.

1. Obtain the latest firmware package for your exact model from Konica Minolta authorized sources.
2. Prepare a USB flash drive formatted in FAT32. Copy the firmware files to the root directory (including the MSC‑specific file, often named “MSC_xxxx.bin” or included in the main firmware set).
3. Power OFF the machine completely (unplug if necessary).
4. Insert the USB drive into the machine’s service USB port (usually on the right side or rear).
5. Power ON while holding a specific key combination to enter recovery mode (common methods):
   • Most models: Press and hold the “Utility” key while turning on the main power, then release when the firmware update screen appears.
   • C224e/C284e family: Hold “Stop” and “1” and “3” while powering on, then select “Firmware Update”.
   • C258/C308/C368: Press “Utility/Counter” at power‑on, then “Detail” → “Firmware Update”.
   • Refer to your service manual for the exact recovery entry method.
6. Navigate to “Firmware Update” and select “MSC” (or “All” if the package updates all boards).
7. Start the update. Do not interrupt the process. The machine will rewrite the MSC flash memory.
8. After successful update, the machine should reboot automatically or prompt for a power cycle.
9. If CC164 clears, run a full set of adjustments (gradation, registration).

Step 2 — Use “Error Clear” Sequence to Force Recovery (Some Models)

On certain models (C458/C558/C658, 8‑series), you can bypass the error screen to enter a special service recovery mode.

1. Power OFF the machine.
2. Press and hold the Stop and Start buttons simultaneously, then power ON while holding them.
3. Continue holding until the machine displays “Firmware Update Mode” or “Error Clear Mode”.
4. Proceed with USB firmware update as described in Step 1.

If the machine does not respond to any key combination and immediately shows CC164, the MSC board may be completely non‑functional (dead flash). Proceed to Step 3.

Step 3 — Perform MSC Board Replacement (If Firmware Recovery Fails)

If multiple attempts to rewrite the firmware fail (the update process may finish successfully but CC164 reappears after reboot, or the update itself fails with a write error), the flash memory hardware is defective. Replace the MSC board.

MSC board part numbers (examples):
– C224e/C284e/C364e: A2X0H00200
– C454/C554/C454e/C554e: A79FH00500
– C258/C308/C368: A7PUH00600
– C458/C558/C658: A79JH00600
– 227/287/367: A5C4H00500
– 654/754: A0FDH00400
– 223/283/363/423: A0FDR71100

Replacement procedure:

1. Power OFF and unplug the machine.
2. Remove the right‑side cover and any boards obstructing access to the MSC board. The MSC board is typically a smaller PCB near the main controller.
3. Disconnect all flat cables and harnesses attached to the MSC board. Take note of their positions.
4. Remove mounting screws and extract the board.
5. Install the new MSC board, reconnect all cables correctly.
6. Power ON. The machine will likely show a different error (e.g., C‑xxxx for firmware mismatch) because the new board has no valid firmware for your region/options.
7. Immediately perform a full firmware update (MSC and all other boards) using the latest firmware package.
8. After successful update, perform necessary adjustments (gradation, registration, scanner calibration).

Step 4 — Check for Firmware Version Mismatch Between Boards

In rare cases, CC164 can appear after a firmware update that only partially succeeded — for example, the MFPB was updated to a newer version but the MSC remained on an older, incompatible version. The checksum may fail because the MSC firmware expects a certain handshake that the new MFPB firmware changed.

1. If you can occasionally access service mode (even intermittently), check the firmware versions of the MFPB/PRCB, MSC, and other boards.
2. All boards should run firmware versions that are listed as compatible in the release notes.
3. If a mismatch exists, update all boards to the same package version simultaneously (use “Update ALL” if available).

Step 5 — Replace MFPB / PRCB / BASEB (Last Resort for Integrated Models)

On models where the MSC function is integrated into the main control board (e.g., i‑series, some e‑series variants without a separate MSC board), replacing the MSC board separately is not possible. In these cases, CC164 indicates that the main board’s flash memory region for image processing is defective.

• Replace MFPB — for C258/C308/C368, C458/C558/C658, 458e/558e/658e (when MSC is on‑board).
• Replace PRCB — for C224e/C284e/C364e (if no separate MSC board exists — verify with service manual).
• Replace BASEB — for i‑series (C450i, C550i, C650i, 458i, 558i, 658i).

Before replacing a main board, always attempt firmware recovery multiple times (using different USB drives and different firmware versions, including an older version if the latest fails). Main board replacement is expensive and should be the final step.

Quick Reference — Troubleshooting by Symptom

Understanding the CC16x ROM Error Family

The CC16x codes indicate checksum failures on different boards. They all have similar diagnostic and recovery steps.

• CC163 — ROM contents error (MFP): Main controller (MFPB) firmware corrupted.
• CC164 — ROM contents error (MSC): Image processing board firmware corrupted — the subject of this guide.
• CC165 — ROM contents error (PRCB): Printer control board (PRCB) firmware corrupted.
• CC166 — ROM contents error (SCAN): Scanner control board firmware corrupted.
• CC167 — ROM contents error (DF): Document feeder control board firmware corrupted.

Diagnostic tip: If multiple CC16x codes appear simultaneously, suspect a common cause: power supply instability, a failing main board, or a corrupted firmware update package. Address the power supply first, then attempt a full “Update ALL” firmware procedure.

Preventing CC164 From Recurring

• Never interrupt a firmware update. Use an uninterruptible power supply (UPS) during updates to protect against power loss. Do not remove the USB drive or power off until the machine restarts itself or shows “Update completed”.
• Use only genuine Konica Minolta firmware files from official sources. Third‑party or modified firmware can cause checksum errors or brick the board.
• When updating firmware, update all boards together. Mixed versions across MFPB, MSC, and PRCB can cause unexpected errors including CC164.
• Replace the MSC board if it has reached high write/erase cycles. In service mode, some models can display flash wear level. If the MSC flash is near end of life, replace the board proactively.
• Maintain proper grounding and power quality. Electrical spikes can corrupt flash memory. Ensure the machine is connected to a surge‑protected outlet or a UPS with line conditioning.

Professional Technician Summary

Error Code CC164 on Konica Minolta bizhub machines indicates a ROM contents error on the MSC (Memory/Sensor Control) board. The machine cannot boot because the image processing firmware fails a checksum test.

The most common cause is an interrupted or incomplete firmware update. Before replacing any hardware, attempt to re‑flash the MSC firmware using the machine’s recovery mode (e.g., USB firmware update with the machine in service recovery). Approximately 60% of CC164 cases can be resolved by a successful firmware rewrite.

If firmware recovery fails repeatedly (write errors, or the update succeeds but CC164 returns immediately), the MSC board’s flash memory is defective. Replace the MSC board with a genuine Konica Minolta part. After installation, perform a full firmware update to all boards to ensure compatibility.

On i‑series and some e‑series models where the MSC function is integrated into the BASEB or MFPB, CC164 indicates main board corruption. Attempt firmware recovery first; if unsuccessful, replace the BASEB or MFPB. This is a last resort due to cost.

Always verify power supply stability and grounding when CC164 appears without a recent firmware update. Electrical anomalies can corrupt flash memory. After resolving CC164, recommend a UPS for the machine.

Unlike mechanical or sensor errors, CC164 cannot be fixed by cleaning, reseating cables, or replacing fuses. Firmware recovery or board replacement is mandatory.