Unfortunately, the answer is no with official version. 

BS2_EnrollUser API transfers the total BS2UserBlob structure. SDK overwrites the total user information whenever it updates user information. 

If you want to send only updated information, you need both custom SDK and custom FW by device type are required.

If you don't want to waste memory in your application & don't use user profile picture, you can use BS2_EnrollUserSmall instead of BS2_EnrollUser.

The BS2UserBlob structure includes BS2UserPhoto, the largest capacity of the userblob. However, BS2UserSmallBlob can greatly reduce to hundreds of bytes of structure.