If you own an H series 6300, 6350 or 6400 Samsung Smart TV, make sure you do not allow the set to download the recently released 2125.1 firmware. Make sure to disable your automatic firmware upgrade feature in the TV's system settings. Otherwise the TV will automatically download the firmware without your permission thus making it impossible to disable the Automatic Dynamic Contrast feature on the set. It will be stuck on FULL BLAST, rendering the TV unwatchable by serious tuners.
Take note: You will still have the ability to turn off the dynamic contrast tab, but the TV will refuse to obey your setting's command. Remember, there is NO GOING BACK once the set has downloaded the faulty firmware. Good luck!

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