Oppo quickly caught on. Within two weeks, a new OTA silently rolled out that downgraded the charging speed if it detected the “leaked” firmware — but it couldn’t touch phones that had never connected to the internet after flashing. Those became “zombie fast-chargers,” traded in offline markets for double the price.
To this day, old repair shops in Ho Chi Minh City and Jakarta still whisper about the “A1601 firmware unlock” — not for root, not for custom ROMs, but for the forbidden 20W charge that Oppo didn’t want you to have.
Want me to dig into the technical reason Oppo locked it, or the custom firmware scene that later emerged for the F1s?
No. Oppo stopped official updates at Android 6.0/7.1 (depending on region). Any claim of official Android 9+ for A1601 is false. To get higher Android, you must root and install a custom ROM (not recommended for beginners). firmware oppo f1s a1601
If you are nervous about flashing, an Oppo service center will flash the official firmware for a small fee or even free if under warranty.
There are two primary methods. Method 1 is the safest for beginners.
Yes, a clean firmware flash removes years of cached data, broken app leftovers, and software rot. It will feel like day one. However, hardware degradation (battery health, eMMC wear) cannot be fixed by software. Oppo quickly caught on
Some users flash firmware from different regions to change the language pack or remove carrier bloatware pre-installed by local distributors.
When the Oppo F1s launched, it advertised “VOOC Flash Charge” — but only on paper. The reality? Shipping units had no fast charging. Users were furious. Oppo’s official stance: “Hardware limitation in certain regions.”
Then, a leaked internal firmware build — A1601_EX_11_A.14_161102 — started circulating on XDA and Vietnamese forums. It wasn’t an official OTA. Its changelog had a single, cryptic line: Want me to dig into the technical reason
“Updated power management profile for specific adapter compatibility.”
Users who flashed it discovered something impossible: the phone suddenly charged at 5V/4A (20W) — real VOOC speeds. How? The firmware re-enabled a hidden PMIC (power management IC) mode that Oppo had artificially locked to avoid paying Qualcomm licensing fees for Quick Charge (the F1s used a MediaTek chip but borrowed Oppo’s own VOOC circuitry from higher-end models).
Yes, if:
No, if:
The Oppo F1s A1601 is a legend of its era, but even legendary firmware cannot bypass hardware limits. A clean flash will give you a snappy, stable phone for calls, WhatsApp, YouTube, and casual use.