as said, in theory there is a fix from 4.1.2 dlk7 and up versions., they'll not fix the phone (well in fact if you are in china they'll do) due to the fact that they'll lose money with it(it is easier to wait til phone dies or til the warranty is over)
and referring to the rom question, if they see that there is the binary changed and another rom, they'll make things more difficult to fix it.
I recommend you to install emmc brickbug check from playatore and run the memory test. if you pass it in fact there is no reason to worry about SDS if you continue using Roms with the fix (almost all of them have the fix, but ask first)
hope I clarified and helped, bests
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