Can I downgrade my phone to the lower Android version?
Where can I download ROM or firmware for my phone?
How to downgrade my phone?
How to unlock Bootloader(BL)?
How to flash the firmware?
Can I install the firmware of other phones in my vivo phone?
How to access Recovery mode?
Is there an international firmware for the phones such as X21 sold in Chinese Mainland?
How to exit the Fastboot mode?
It prompts "Decryption unsuccessful" while installing the firmware. What should I do?