Power off the phone, disconnect and reconnect the battery(if possible) and connect USB cable...
Using Port:
AUTH info: MTK, version: 1
Boot META MODE...
Hold the VOL UP to force MediaTek BootROM.
Scanning BootROM or Preloader port... Done.
Detected MediaTek PreLoader USB VCOM (Android) (COM119)
Connection status: IUSB3HUB:USB 2.0 Full-Speed
USB Driver: [MediaTek Inc.] usbser, version: 2.0.1118.0, date: 4-29-2011
Boot META MODE from PreLoader ... Done.
Scanning META port... Done.
META port detected: MediaTek PreLoader USB VCOM (Android) (COM119)
Boot META MODE successfully.
Modem info:
BaseBand chip: MT6750
SW time: 2000.00.00
DSP firmware version: 1.0
DSP patch version: MOLY.LR11.W1603.MD.TC16.JAD.SP.V6.P21
SW version: OPPO6755_C66_N1_HW
HW version: Unknown
Melody version: LWCTG_MP3_50
AP info:
Platform: MT6750,S01
Build version: CPH1717EX_11_A.14_180824
SW version: CPH1717EX_11_A.14_180824
SW time: Fri Aug 24 00:41:15 CST 2018
HW version: S01
Writing imei...
imei[1]: 865524030125754
imei[2]: 865524030125747
failed