Roland FP-4 Owner's Manual page 58

Saving Your Favorite Performance Settings
Storing the Registration
4. Release the [Registration] button.
Your performance settings will be saved.
The [Registration] button will change from blinking to lit.
NOTE
To select the performance settings you saved, refer to "Recalling a Registration" (p. 59).
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Never turn off the power while settings are being saved. If you do so, the FP-4's
internal memory will be destroyed, rendering it unusable.
You can return the content saved at a [Registration] button to the factory-set condition.
Refer to "Restoring the Factory-set Condition (Factory Reset)" (p. 91).