On this page, you will find the official link to get the Oppo A57 CPH1701 Stock ROM (Firmware, Flash File). The Stock ROM package comes as a zip file, and it contains Firmware, USB Driver, Flash Tool, How-to Flash Guide.
The Oppo Stock ROM can update the device, downgrade the device, fix the device facing bootloop issue, or any software issue. You can use the following link to get the ROM on your computer.
Firmware Name: Oppo_A57_CPH1701_EX_11_A.35_11_35_20180809_OTA.zip
Firmware Size: 2 GB
How to Flash: Copy the update.zip file to Phone SD Memory and Flash it from the recovery menu.
[*] Backup: We recommend you to take a backup of your personal data from the device, as flashing or installing the ROM using the Flash Tool will permanently delete your personal data from the device.
[*] Original firmware: Our firmware is 100% authentic and is officially released by Oppo Mobility LLC. We have scanned the above firmware using the Kaspersky Antivirus before sharing it online.