Use the following steps to view the ROM version in the HPD-15:
Note: Each button press and release is time sensitive, so it may take a few tries until the version appears in the display.

1. Power on while holding EDIT and CHAIN.

2. Release EDIT (continue to hold CHAIN) and press PATCH SEL.

3. Release CHAIN (continue to hold PATCH SEL) and press EDIT.

Each button press or release must be done within two seconds of each other. If not, the Handsonic will power on in its normal operation mode.
If the steps are performed correctly, the current version will appear in the display.
To EXIT this mode, turn the power off.