Step 1: Download Lenovo S90 Stock ROM Firmware zip file in your PC and extract it. (It includes Scatter files, SP Flash Tool, and Drivers).
Step 2: Download Lenovo USB Drivers in install in PC. If already installed quit this step.
Step 3: Power Off / Switch of your smartphone (it is better to remove battery after switching if possible)
Step 4: Go to extracted folder “extracted in Step 1” > SP flash tool > you will see Flash-Tool.exe > Open this to Launch setup.
Step 5: One setup is launched Click on > Download Tab > Scatter Loading. Now locate scatter firmware file (Present firmware folder extracted in Step 1) and load it.
Step 6: Connect your device with PC via data cable (Keep in mind the device should be switch Off). Now click on Download Button / Upgrade Button (having sign of Green Arrow) to begin flash Flashing.
Step 7: Wait Until process complete. In end of Successful Flash Lenovo S90 Stock ROM Firmware, a Green dot / ring will appears.
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