Go to Settings > Fingerprint, Face & Password . Try to register your fingerprint. If the sensor doesn't vibrate or the menu crashes, the flashed firmware is for a different hardware revision. Demand a refund.
If you are searching for this term, you aren't just looking for a cheap phone. You are likely looking for a device that has been wiped clean, repaired to "like-new" software standards, or saved from a software brick. This article dives deep into what "flashing" means, why the Oppo F9 is still a fantastic buy in 2025, and how to navigate the refurbished market safely. flash oppo f9 refurbished
The phrase represents a niche but vibrant corner of the smartphone economy. It represents repairing the broken, unlocking the locked, and recycling the old. Go to Settings > Fingerprint, Face & Password
Modern phones have abandoned the 3.5mm jack. The Oppo F9 still has it. It also supports up to 256GB of microSD expansion. For media consumers and budget travelers, this is a killer combination. Demand a refund