As mentioned in a previous post, the new Intel Skylake generation ProDesk 600 G2 Desktop Mini supports both M.2 SSD technologies with either SATA or NVME interfaces (HP Turbo Drive G1 and G2). There may be confusion around the 2 M.2 slots, however. There is a M.2 PCI-e X1 slot where a WIFI card can be configured by HP, and there is a 2nd M.2 PCI-e X4 interface dedicated to the SSD.
The BIOS on this generation can see and boot from either M.2 SSD technologies.
Hope this clears any confusion