You use it to fix problems that the stock firmware cannot address, specifically FRP (Factory Reset Protection) and dead boot conditions.
The A035F is notorious for corrupting its persist or nvdata partition. When the device shows a black screen and only a blinking red/blue light when connected to a PC, the bootloader is stuck. The PAC Combination file contains a low-level FDL (Fast Download Link) sequence that re-initializes the Unisoc processor, bringing the device back to life long enough to flash the stock ROM. A035F U2 File PAC -Combination-
Service centers use the Combination file to run RF (Radio Frequency) tests. For the end-user, it allows access to the *#0808# USB settings and *#0011# service mode to force LTE bands or diagnose hardware failures. You use it to fix problems that the