Here you can find to download all Official Oppo Flash File Firmware ROM for free. You can use it mainly to fix the problems like being stuck at the boot logo, hanging on the logo, Removing screen lock, and many more other Android problems.
Also, you can use this file to remove pattern, password, & FRP lock, upgrade OS, fix bugs, unroot, Delete Malware, Viruses, & unwanted application from your phone. Make sure, before downloading the firmware always check the firmware version & device model by click on the emergency call and dial *#899#, and then download the latest or same version of Oppo Stock ROM to flash your phone.
The firmware comes with a zip file and it contains Stock ROM, USB Driver, Flashing Tool & How-to Flash Manual guide.