Ensure the device has at least 60% charge to prevent it from turning off during the process.
If the phone had a Google Account signed in prior to the lock, simply flashing the firmware via FTF may trigger Factory Reset Protection (FRP) . When the phone boots up, it will ask for the Google email and password that was previously synced on the device. You cannot bypass this without the original credentials. The FTF lock removal only solves the local screen lock, not the cloud-associated FRP lock. sony g8341 lock remove ftf
Removing a screen lock from a Sony Xperia XZ1 (G8341) Go to product viewer dialog for this item. Ensure the device has at least 60% charge
If you accept losing all data: