He downloaded OPPO A37m EX_11_A.15_170919 (Global firmware from Indonesia—a known stable version). Using SP Flash Tool in "Firmware Upgrade" mode (not "Download Only"—that would erase his IMEI), he flashed the global ROM.
The phone must be in for the PC to write the new software: Power off the device completely. Hold both Volume Up and Volume Down buttons. Plug the phone into the PC while holding the buttons. oppo a37m china to global firmware
Converting to Global firmware aims to solve these issues. The Global ROM (typically identified by a version number ending in specific region codes) offers: He downloaded OPPO A37m EX_11_A