if version 7.0
just downgrade to 6.0.1
now root phone via odin
download cf auto root and flash it done
dowload z3x version 28.1
go to repair no download mode
phone must be onno need to write imei in imei box
just press patch certificate
its done
precess
download twrp
flash via odin in odin reboot system must be un ticked
after twrp flash before mobile on
press vol up + home + power
here twrp option comes
(put supersu file in sd card) click install
doneee
prodeuce to reset frp
download apk file easy frp apk from link
put apk file in sd card
watch youtube video enable adb mode
comple on mobile and connect cable
if ask allow usb dubbing allow it
if not sucess reset frp in z3x
here usb dubbing popup comes allow it
reset frp by z3x or tool
after frp reset phone must be reset from setting
after frp reset dont remove sd card
restart mobile when complete on sd card pop show
open sd card install easy frp select option 2
go to setting and reset mobile doneeeeeeee
oppo f3 cph1609 (mtk 6755) frp pattern done in miracle box open miracle box 8th boot (65xx&mt67xx/8127) untick safe mode click formet here notification comes press no to continue and start and done done