Downgrading Kitkat 4.4.2 to 4.2
I managed to get my HTC One Dual Sim to 4.4.2 Kitkat (European version) - happy with the software
BUT, I am unhappy with the bluetooth, it is not functioning well in my car, sometimes connects, sometimes doesn't connect. How can I downgrade it to the previous version 4.2? Please guide me the steps and download links.
Thank you all