I have a HifiBerry DAC+ board which I can't get to boot on a RP 2. Tried with two different RP 2 boards, 3 different distros (piCorePlayer, Raspbian and Max2Play) and two different power supplies (both 2A).
Act led is only flashing once at power on. Then it is off for a long time and start steady blinking 8 times, indicating SDRAM or power issue I think.
If I remove the DAC+ board it will boot fine.
I have not check the serial console yet. I assume I can use GPIO14/15 (Tx/Rx) even when the DAC+ is connected.
Anything else I can check on the board like voltage?