Banking app detects previous root I have a Sony xperia Z (C6603). A while back I rooted the device but then later I did a factory reset and unrooted it. Sadly I have forgotten exactly what software I used for rooting/unrooting.

Now the phone works perfectly for everything I do except for my Barclays Bank app which declares "Sorry, the Barclays Mobile Banking app does not support rooted devices".

I have tried mutilple root-detection utilities and they all insist the device is no  longer rooted.

Is there anything I can do to fix this?
If the App is using SafetyNet it also detects that your Bootloader is unlocked. So if your BL is still unlocked you will need to Lock it for the App to work.

I dont have a Xperia Z but this seems to explain how to do that:
Link to xda


Download the latest Flashtool ( found in OG android development forum) 
Install the Flashtool drivers found in the drivers folder
Connect phone in Flash-mode (phone shut down, volume down + power)
Press the BLU button
Press the relock option
Put a stock .tft firmware in the Flashtool firmwares folder (this is required!!)
Flash the firmware (this is required!!)
Done