Playing with this handset for 10 days
Success 1000% by HardnSoft
Vivo Y71 IMEI was corrupt due to flashing
No backup anywhere
Whole process here
Thanks to UMT Dongle
1.First downgrade full flash with version PD1731F_EX_1.6.3
2.Turn on phone and complete settings
3.Then write eng modem file with umt qcfire
4.Turn on phone enable diagnostic port by code *#558#
5.Then use qualcomm imei write tool
6.reboot phone to see changes
7. then write original modem only from firmware
Job done
Success 1000% by HardnSoft
Vivo Y71 IMEI was corrupt due to flashing
No backup anywhere
Whole process here
Thanks to UMT Dongle
1.First downgrade full flash with version PD1731F_EX_1.6.3
2.Turn on phone and complete settings
3.Then write eng modem file with umt qcfire
4.Turn on phone enable diagnostic port by code *#558#
5.Then use qualcomm imei write tool
6.reboot phone to see changes
7. then write original modem only from firmware
Job done