An incorrect firmware mismatch can cause a hard brick. Version 1.5 is generally safe, but no tool is 100% foolproof.
To understand why Samsung FRP Tool V 1.5 is effective, you must understand FRP’s weakness. FRP data is stored in the /data partition, specifically within the system/users directory. When a user performs a factory reset manually (via recovery mode), the phone wipes user data but may leave certain locks intact. Samsung Frp Tool V 1.5