Hi machupo, we have to note that the SATA and mSATA interfaces are separately wired, internally. However, Intel® NUCs were designed to use one storage device in the corresponding interface and this type of integration has not been validated.
I am sorry for any inconvenience.
Well, someone has to try it first
Guess that's me!
I recomed use of external DC-DC regulator, for example on XL4005 (up to 5A), you can connect it to internal pins of DC IN of NUC, and connect pin 4 of XL4005 (disconnect them from DC-DC board first) to +5V SATA to control powering on when start NUC.
But I have other problem - MPX-3132 not works on D54250WYB (I trying to use in upper mini PCIe slot instead of SSD).
Do you have this problem or not?