The download includes the instructions in the Read Me file:

============ CP4 STAGE/CP40 STAGE V1.01 Operating System Updater Readme ============

Thank you for purchasing the Yamaha CP4 STAGE/CP40 STAGE Stage Piano.
This Readme file contains important information about the CP4 STAGE/CP40 STAGE V1.01 Operating System update and the updating process.
Please read this document carefully before updating your CP4 STAGE/CP40 STAGE.

NOTICE:
- This updater is only for the CP4 STAGE/CP40 STAGE.
- This updater is to be used at the user's own risk.
- All User data (Performances and so on) will be initialized by this updater. Please make sure that you have saved all User data to a USB flash memory before performing this update.
- The unit may become inoperable if the electrical supply is interrupted while running the updater (by disconnecting the AC cord, etc.). If this happens, run the updater again from the first step.
- If the unit does not function after running the updater, please contact your nearest Yamaha service center.
Yamaha Global Gateway
http://www.yamaha.com/countries/index.html

This update is applicable to the following version:
CP4 STAGE/CP40 STAGE with firmware versions V1.00

How to check the version of your CP4 STAGE/CP40 STAGE

1. Press the [UTILITY] button, and press the [«] cursor button several times until "07:Job" is displayed, then select "07:Job" and press the [ENTER] button.
2. Press the [«] cursor button several times until "02:Version" is displayed, then select "02:Version" and press the [ENTER] button.
3. The following message will appears at the top of the display:
-------------------------------------
Boot:*.** Firm:*.**
-------------------------------------
The unit's version is indicated by "Firm:*.**".

Updating Procedure

NOTICE:
All User data (Performances and so on) will be initialized by this updater. Please make sure that you save all User data to a USB flash memory before performing this update.

Required Items
- One USB flash memory of over 16MB capacity formatted on the CP4 STAGE/CP40 STAGE.

1. After downloading, copy the uncompressed following files to a USB flash memory. No other files should be present on the USB flash memory.
CP4_40SETUP.PRG

2. Power off the CP4 STAGE/CP40 STAGE.

3. Connect the USB flash memory prepared in step 1 to the USB [TO DEVICE] terminal of the CP4 STAGE/CP40 STAGE. Hold down the [PLAY] button, then power on the instrument.

4. After the message "[PLAY]: Install" appears at the top of the display, press the [PLAY] button.
The update version is indicated by "ver.*.**" at the bottom of the display.

5. The updater process begins when you press the [PLAY] button again.
The updater will begin with the "Checking File," "PROG Erasing," and "PROG Writing **%" messages.
When the "Completed. Program is ver.*.**." message appears, the update completed.

NOTICE:
DO NOT power off or remove the USB flash memory from the CP4 STAGE/CP40 STAGE until the "Completed" message appears. If the electrical supply is accidently interrupted while running the updater (by disconnecting the AC cord, etc.), the unit may become inoperable. If this happens, run the updater again. If the unit still does not function after doing this, please contact your nearest Yamaha service center.

6. Power on the CP4 STAGE/CP40 STAGE.

This concludes the update process.

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Main Fixes and Enhancements

- Fixed a problem in which, when turning on the layer part, pressing a key, then turning off the part while holding the sustain pedal, the sound of the layer part continues even though the key and sustain pedal have been released.

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The company names and product names in this release note are the trademarks or registered trademarks of their respective companies.
Copyright(c) 2014 Yamaha Corporation. All Rights Reserved.