The CM14.1 ROM is based on AOSP therefore to flash it your device's bootloader should already be unlocked. And since this is a modified ROM wrapped with .zip extension therefore to install it on your OPPO R5 then you are going to need a custom recovery such as CWM or TWRP. I choose TWRP because it has a better user interface.
And if you are interested then you can start by firstly read the following preconditions to give you useful information about what to prepare before you begin.
- Before you start I recommend you to backup every data you regard important.
- You need to enable USB debugging mode of your Android powered device. (How to enable USB debugging mode on Android).
- And remember that this guide is only for OPPO R5, forget about the guide, if you don't own the phone.
- Do not forget to firstly unlock your OPPO R5's bootloader before starting.
- This is also a requirement, your OPPO R5 device should already be powered with either CWM or TWRP recovery. (How to install TWRP recovery on any Android devices).
- Remember that you need to have a computer or a USB cable.
- Follow all the instructions from A to Z and skip not anything.
How to update OPPO R5 to Android 7.0 Nougat with CM14.1 ROM
Follow the guides from this post at your choice, blame none but yourself, if you brick or damage your device..
- Now you must download Android 7.1 CM14.1 ROM and Gapps to the computer of yours.
- Now you need to use your USB cable to connect your device to PC. Once they're connected then transfer all the zip files to your device's SD card.
- Now power off your OPPO R5 then unplug it from USB cable.
- Now enter to the Recovery Mode / TWRP mode.
- Inside the TWRP mode, perform the following action full data wipe by choosing the Wipe button -> Swipe to Factory Reset button.
- Now back to the TWRP main menu then you need to tap the Install button. And then choose the Android 7.0 CM14.1 Nougat ROM zip file you previously transferred to your device's storage on step 2.
- Now confirm the installation by simply swiping the Swipe to Confirm Flash option. You will see the installation will begin.
- Once the installation has been completed then repeat the above action to flash the Gapps.
- Now you need to tap Wipe cache/dalvik button in case you experience bootloop or other technical problem.
- Now you need to tap the Reboot System button.