I don't know where the opinion comes from that putting it to factory is the best way to start from beginning. The most tries fail, because the firmware image is in the wrong format.
If you really can get into failsafe mode, try to follow those howtos:
Failsafe mode with USB Support
Failsafe mode without USB Support
If you really can get into failsafe mode, try to follow those howtos:
Failsafe mode with USB Support
Failsafe mode without USB Support