Flashing the firmware via Odin (the tool we will use) usually wipes the user data partition. Even if the process doesn't wipe data, there is always a risk of failure. Backup your photos, contacts, and messages to an external SD card or cloud storage.
🔐 Warning: Flashing unofficial firmware trips (0→1), permanently disabling Samsung Pay, Secure Folder, and warranty. samsung j7 2016 flash file