Steps to Install Lineage OS 15 Android 8.0 Oreo on Galaxy C9 Pro Duos:
Step No 1: – First, download Lineage OS 15 Android 8.0 Oreo custom ROM for Galaxy C9 Pro Duos on the desktop of the PC.
Step No 2: – Plug your device to the PC using its USB data cable and mount its USB memory storage.
Step No 3: – Transfer Lineage OS 15 Android 8.0 Oreo ROM .zip file which you’ve already downloaded from the above link to the root folder of your SD card on the phone.
Step No 4: – Unplug the Galaxy C9 Pro Duos from the PC and power it OFF to boot into Recovery Mode.
Step No 5: – Power ON the device while pressing and holding Volume Up + Home + Power buttons at the same time to enter into Recovery Mode.
Step No 6: – While your device is now in CWM Recovery, perform wipe data/factory reset, wipe cache partition and wipe dalvik cache also by navigating to Advanced > Wipe Dalvik Cache.
Note: – wipe dalvik cache will help you to prevent boot loops and other errors while ROM installation.
Step No 7: – Go back to the main Recovery Menu and choose to install zip from SD card → choose zip from sd card.
Step No 8: – Navigate to the Lineage OS 15 Android 8.0 Oreo custom ROM .zip file which you’ve already transferred to the SD card of your device previously. Select the ROM .zip file using the Power button and confirm the installation to begin.
Step No 9: – Navigate to +++++Go Back+++++ once the installation is completed. From Recovery Menu, reboot your device by selecting reboot system now.
Your Galaxy C9 Pro Duos will be rebooted and may take about 4 to 5 minutes to boot for the first time after installation.
Done! You’ve successfully updated Galaxy C9 Pro Duos to the latest Lineage OS 15 Android 8.0 Oreo ROM.