Chosen Solution
I plugged my phone in to charge overnight and then woke up to this. Does not boot when i try switching it off and on again. Have removed the battery and put it back in. Have opened it up and reseated the screen connecter. Is it an easy fix or will i need to book it in for board level repairs?
Rainbow colors as in all the pixels individually are random colors on the screen? If yes that is eMMC failure (The memory chip on the logic board that stores all data for firmware and user data is corrupted). Not an easy fix unfortunately, to get this fixed it requires replacing (board-level repair) and/or reprogramming that chip via a JTAG box. Not worth getting it fixed unless the data on it is really important.
