It's been a month since i upgrade my lumia 520 to windows 8.1 .Now ,I am facing a big issue of charging.I cannot charge my phone using wall charger .It chargers perfectly using usb cord via pc. It shows (undetectable or malfunctioning only in notification for few seconds) on my pc but it charges perfectly using usb and also i can access phone data and memory card without any problems . I even tried to reset my phone but it didn't work out .So if anyone got solution or suggestion ,will appreciate it .Thank you !