1.Does the disc that you posted the scan for, play in a stand-alone player?
2. Can you post the error log for the failed burn?
A) Flashing your drive with unofficial firmware voids your warranty, you knew that before flashing your drive, so you should bear the responsibility.
B) Resetting the learnt media eeprom probably won't help much now as you have cross-flashed your drive which resets the learnt media memory anyway. Your burns may improve some, but that scan is pretty bad. Usually it takes 3-4 burns before a consistent level of performance is achieved. If you do want to try that, make sure you back up your eeprom first, and read all the readme's and instructions included until you are SURE what you are doing.
C) I don't know about polarized lenses, but I think your problems won't be solved by cleaning your lense, unless you burn in a very dirty or smoky atmosphere.
You should be getting better results from that firmware and media, but you may want to try media that is known to be consistently excellent so as to rule out poor media as a cause. The slow demise of the quality of your burns could be the slow demise in the quality of the media, due to manufacturing inconsistencies, not your drives fault. However, since you are unable to get one good burn, it may be your drive that is bad. Try better media as a test...if it fails, then you will have good media for a new drive:).