preschiousb you need to treat those phones like any other phone with water damage. You should not expect those to work without any intervention. At least try the basics by disassembling your phone, remove the logic board and clean everything with 90%+ isopropyl alcohol. Remove the EMI shields from your boards. Then replace the battery and re-evaluate. Use [guide|5825|this guide] to get an idea on how to do it. It was written for an iPhone but all the points are still pertinent to your phone as well.