If you are looking for the official stock firmware/flash file for the Vivo X20 PD1709F, you can download it here. The firmware is useful for fixing software related problems like.
- Boot loop
- Unbricking of device
- Un-rooting your phone
- Update firmware
- Restore to factory defaults
- Fix malware/monkey virus etc
Download Vivo X20 PD1709F Stock ROM Firmware/Flashfile
Download the stock firmware for your Vivo below. Flashing is QFIL/Recovery mode(SD Card).