first of all what is dirty flash means? i have not experienced any bugs yet on this build..even a couple days ago, maintainer has released a new build for some reason. but still, no bugs. it was a great rom ever! smooth, gaming is okay and better than A11. for those who said fast charging didnt work. actually it works for me. yeah it does show "charging slowly" but in reality it was fast!.my battery went 20-100 just in 20 minutes
Dirty flash mean flashing without formatting data. The opposite of what we call a "clean flash" which mean starting from scratch and reinstall / reconfigure everything.
Regarding fast charge, I'm going to give my doubts on your score.
A little bit of (dirty) math :
charging 80% of a 4520 mAh battery in 20 minutes (3616 mAh)
is equivalent of charging 10,848 Ah in 1h
Which for a 5v battery means a constant charge of 54.2 Watts
But the device is physically limited to 33W charge.
Even in theory, that's not possible.