The firmware provided here is royalty free but unfortunately is impossible to provide it as open source code by the Microchip policy applied to this device.
The full information are available under NDA so please contact your local Microchip sale representative to know how to have them.
Download the binary image of AVR firmware from this link:
On the YARM-2-DEV adapter switch the MCU selector to the AVR possition.
Launch Atmel Studio 7 and select Tools -> Device Programming, then follow these steps to load the firmware inside the ATA8510 EEPROM
To getting started with Atmel Studio 7 and Yarm read this article: