SD card Pinout

1. DATA3
2. CMD
3. VSS1
4. VDD
5. CLK
6. VSS2
7. DATA0
8. DATA1
9. DATA2

eMMC Pinout

A3. DATA0

A4. DATA1

A5. DATA2

B2. DATA3

M5. CMD

M6, CLK

the trick bit now is the connection of the power lines and provide supply decoupling. Thankfully I can remove caps from the original board and the plan is to solder them directly to the power pins of the eMMC chip. This is going to be ugly but it only needs to work long enough to extract the data.