An usually refers to a specially patched qcn (Qualcomm Calibration Network) file, a custom persist.img , or a modem patch ( non-hlos.bin ). These files:
Flashing updated modem firmware files can directly resolve Wi-Fi performance issues. redmi note 5 pro wifi fix file extra quality
Yes. 90% of disconnect issues on AOSP-based ROMs ( whyred ) stem from a corrupt persist. The extra quality file resolves this across MIUI, Pixel Experience, and crDroid. An usually refers to a specially patched qcn