Some days ago, i got these message during a recovery session at a Samsung Galaxy Tab A6 (SM-T580):

CUSTOM BINARY (RECOVERY) BLOCKED BY FRP LOCK. The message appeared at Download Mode. FRP means Factory Reset Protection. Please read more backgrounds about this protection utility at samsungs homepage. The background of this blog is how to secure the private data.

There is a possibility to hold the private data on the device if you download the original stock image from a samsung server and transfer it with odin to the device. Please pay attention to choose at the CSC-Option the CSC-HOME-Image. The different between CSC and CSC_HOME is that using CSC_HOME means saving private data from reset-function, it will not be overwritten. You will not loose private data if you use the CSC_HOME-Image.

Another important thing: leaving the CSC-Field blank means resetting the private space; If you mean leaving the CSC-Field blank will ignoring the private space will reset the whole data. Its very important please read the manual bevor wiping data.