I recently purchased a Z2 but it came with a USB cable that doesn’t work. Is it ok to use a different cable or even a charger? Manufacturers always warn about using non-authentic accessories but usb cables look the same. I understand that a non-sony charger can somehow slow down the process (does it really?). So, should I shop for Sony accessories?
Any decent standard USB charger will work no problems. You'll pay a hefty Sony tax if you go down the official route!
