use umt and factory reset in meta mode
logs
Brand/Model : Vivo / *Auto Detect*
Operation : META Reset (Oppo Reset (eMMC))
Checking for exisitng device in META mode...
Existing META Port Found!
Port : MediaTek USB VCOM (Android) (COM27)
Connecting Device...OK
Brand : vivo
Model : vivo 2015
Market Name : unknown
Market Name : unknown
Manufac. : vivo
Build Date : Tue Feb 28 14:38:18 CST 2023
Ven. Date : Tue Feb 28 14:38:18 CST 2023
Platform : MT6765
OEM : unknown
OEM Device : unknown
Disp. ID : QP1A.190711.020 release-keys
Inc. Ver. : compiler02281430
Patch Level : 2023-02-01
OTA Ver. : unknown
Oppo Reset Settings (eMMC)...OK
Operation Finished.
[UltimateMTK2 v0.5]
Log Saved : 20230523_191752.log
logs
Brand/Model : Vivo / *Auto Detect*
Operation : META Reset (Oppo Reset (eMMC))
Checking for exisitng device in META mode...
Existing META Port Found!
Port : MediaTek USB VCOM (Android) (COM27)
Connecting Device...OK
Brand : vivo
Model : vivo 2015
Market Name : unknown
Market Name : unknown
Manufac. : vivo
Build Date : Tue Feb 28 14:38:18 CST 2023
Ven. Date : Tue Feb 28 14:38:18 CST 2023
Platform : MT6765
OEM : unknown
OEM Device : unknown
Disp. ID : QP1A.190711.020 release-keys
Inc. Ver. : compiler02281430
Patch Level : 2023-02-01
OTA Ver. : unknown
Oppo Reset Settings (eMMC)...OK
Operation Finished.
[UltimateMTK2 v0.5]
Log Saved : 20230523_191752.log