For reference, if you need (not Fastboot), the Oppo A37 uses:
It is common for the OPPO A37 to get "stuck" in a boot loop or recovery mode if a button is physically jammed. how to open fastboot mode on oppo a37 better
Install the Android SDK Platform-Tools to use ADB and Fastboot . Execute Commands: Connect your phone to the PC via USB Open a command prompt or terminal in the tools folder. Type adb reboot bootloader and press Enter. Your will automatically restart into fastboot mode. Troubleshooting and Related Modes Fastboot Mode OPPO A37 - HardReset.info For reference, if you need (not Fastboot), the