Tapping eMMC signals on Jetson TK1 development board

I want to tap signals between on-board eMMC chip and CUDA core on Jetson TK1 development board.
Please suggest me a method for the same, as I have learnt from schematics that both CUDA core and eMMC chip are BGA type Chips.

There is no way to probe signals between eMMC and core as no TP(test point) on board.