You may need the latest update for your particular model. I gather there isn't a universal firmware, but rather specific to your model.
RPM Noise- yes, I used to get it and then I insulated everything with that Velcro backed shielding/insulation wrap. No more RPM noise related fault codes.
Good job, I have to get some of the Velcro shielding this time around. I used aluminum foil encased in black woven wire casing last time, it was effective but not as pretty as I would have liked. Keep us informed and good luck.