achim71 & adminX: thank you very much for posting this important information. I plan to use a mSATA card as NAS (Samsung SSD 850EVO 1TB) too.
Does this dual-purpose slot auto-detect whether there is an mPCIe or mSATA card inserted? Or must it be configured in some config file of the OS.
Does the OS auto-detect when the 2.4GHz wifi card get's moved to the mCPIe slot above the SIM card adapter?
Also, could you briefly describe the steps, how to get the mSATA drive working after it is detected. The Turris documentation regarding NAS installation is not yet translated to English.