Never flash preloader from another device – it hard bricks Oppo A37m.
The Oppo A37m can run custom ROMs, but the process is not user-friendly. The "Fix" generally revolves around successfully bypassing the locked bootloader and ensuring the TWRP image sticks. If you follow the steps above carefully, you can revive the device with a newer Android version (typically Android 7.1.2 or 8.1 Oreo via LineageOS ports), giving it extended life.
This is one of the most popular community builds for the A37 series. It is often used to bypass the aging Android 5.1 Lollipop stock version.
