For devices that won't start, you must use a PC-based flash tool.
By following this comprehensive guide, you'll be well on your way to optimizing your OPPO A57 2016 firmware and taking your device to the next level.
Flashing firmware carries inherent risks, including total device loss. This guide is for educational purposes. The author is not responsible for damage to your phone. Always verify firmware integrity and backup your data where possible.
: You’re still stuck on Android 6.0, meaning many newer apps won't install. Oppo A57 (2016) - Full phone specifications - GSMArena.com
For – Android 7.1.1:
The Oppo A57 (2016) Go to product viewer dialog for this item.
A: No. The last security patch was from 2018. Using this phone for banking or sensitive data is not recommended.