Search on XDA Developers Forum (OPPO F1s section) for "Stock Firmware 712" – Look for posts by Recognized Contributors with high post counts.
If you are specifically looking for a version of Android 7.1.2 that "works" on this device, you must look into rather than official stock firmware. Stock Firmware (Official) : oppo f1s firmware download 712 work
The setup wizard appeared. Select language. Connect to Wi-Fi. Sign in to Google. Search on XDA Developers Forum (OPPO F1s section)
Not dead as in a drained battery. Dead as in a digital corpse. oppo f1s firmware download 712 work
Even with a verified , errors occur. Here’s how to fix them.
Oppo provides an official "Oppo Flash Tool" for service centers. Look for OF F1s_712_MT6750_Android5.1.zip .