✓Wipe Data / System / Art / Dalvik
If necessary, we flash userdata
✓Reboot, give time for initial setup.
We gain patience, the setting takes about 15-25 minutes.
✓After initial setup, restart again. it may seem that the system is slow
I found this ROM on the net, and it is originally developed by "Ukrai_ne" for A1.
It seems he is Russian and so I couldn't contact him.
I put the explanations and the rom here, hope somebody contact him and ask him for a thread in XDA so everyone can use it.
I have tested it, its working, no problem.
You can install it by regular steps of downgrading to 8.1 stock rom (if you have 9v rom) and installing miui roms.