You mentioned the Samsung lib isn't working for sound. Unfortunately you might have to build your own from scratch, enough has changed in 4.4 compared to 4.2 to cause problems. 4.3 and 4.4 aren't that different api wise though, I wonder if there's a device running 4.3+ with the same / similar audio hw to the tab 3 you might be able to shoehorn the driver from
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