It's not a battery problem, because it works over cable in Ubiboot rescue mode for long time, but cannot write anything to eMMC.
So resoldering eMMC(hard or impossible part) or finding N950 with broken screen(which is unavaible to buy, so such n950 is only useful for parts only) is probably the only option.
Because My n950 is generally in good shape, but got dent over power buttons(making them unclickable), it's probably smart to find n950 in perfect condition, but with broken screen(because happily mine is in good shape, from what I saw in Ubiboot green terminal ;-)