I compiled an update ZIP file with the lastest firmware/modem from MIUI v220.127.116.11.
You can flash it from TWRP directly.
I tested it on Ressurection Remix v5.8.0 (Nougat 7.1) and TS Cyanogenmod 13 (Marshmallow 6.0.1).
I don’t know if and what problems are fixed. Please test and share your findings.
I just provided you with updated firmware from official Xiaomi.
This is my first day with this firmware and all seems perfect for me.
Give it a couple of days and report back.
I’ve tried flashing the 18.104.22.168 firmware update I built myself a week or so ago, and I’m positive it doesn’t fix the touchscreen or the battery level, or the 2% battery bug so don’t hope for anything like that. At best there’s a bit of an improvement in signal reception, and even that might be subjective.
The touchscreen issue and battery bugs all seem to be kernel-level problems that need to be fixed with a freshly compiled kernel that includes the fixes made in recent MIUI builds.
If anyone had both the time and the knowledge to fix these issues we’d probably have the fixes by now; sadly the Mi4c is not a new device anymore so don’t hold on to hope too much.