are you getting: "Raw data transfer failed: Invalid argument" error message on every flashing attempt?

There isn't much that you can do if you do, as that usually just tells that there is a problem in transfer or crc error, meaning usb port timings/wrong usb port/distribution probelms, or using usb hubs, etc. If your sure that you have tested in multiple machines and with different ports then in that case you should just take device back to Nokia Care for warranty fixing (all devices should still be under 1.5year factory warranty). Nokia webpages also have imei checker page where you can check if your device still have factory warranty.