In my S9 , Power Mode .>>> Max power saving is selected by default and cannot change to high performance, optimized or medium power saving option. Adaptive power saving is off by default. When selecting any other options, the screen shows changes in brigtness in %, screen resolution then after applying shows turning on and progress moves to 100%. No changes happens in phone, changes back to maximum power saving. Due to this problem, many options in phone will not work including wifi file transfer.
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