I have tried without success to flash the Firmware files with 'Odin' to the phone. The stock files I have downloaded were from both Sammobile and Frija and when unzipped are BL AP CP and CSC. I am now trying to use a programme called Heimdall to flash the phone but having searched the web I cannot find the way to convert the Firmware files to the .gz extension that Heimdall requires. Apparently it has something to do with unzipping the files down the their individual content and then bundelling them into one .gz file to insert into the Heimdall GUI. Any ideas would be of help. Kind Regards.