OK, this is freakin' weird...
I have been running KitKat on my F180S pretty much from the time it got released (different versions: full stock, VDT, Sling...). Yesterday, out of the blue, my digitizer started getting crazy with ghost touches in the upper portion of the screen (around the strip where Q-slide apps usually are in the notification shade, or the clock area on a weather widget where most people have it). This made the phone 100% unusable, as it was constantly
registering touches. Rebooted to recovery to do a factory reset, and the problem was persistent in the recovery, too (I am using PhilZ Touch). So, at that point it looked
like a hardware issue to me. To clear my consciousness, I opened the phone, disconnected the digitizer, cleaned the connectors, plugged it in again. No dice.
Still, I thought about reflashing a full stock KDZ, just for the heck of it (no root, no custom recovery, locked BL). Here is what happened:
1. F180S V30c KitKat - same problem.
2. F180S V30b KitKat (downgraded a notch) - same problem.
3. F180S V20n Jelly Bean
- everything is working fine, no ghost touches. Huh?!?
4. Rooted V20n, unlocked BL (Mako method) and flashed CWM using FreeGee - no problem, everything is still OK.
5. Flashed my favourite JB ROM
- no problem, everything is still OK.
So, the phone is now running on rooted JB, with unlocked BL and CWM recovery, with no touchscreen problems whatsoever. I may try going to KK again at some point, but will just leave it for now, as I need a stable working phone.
WTF??? I am just scratching my head, trying to understand where the issue came from. It appears to be directly related to KitKat, since eliminating unlocked BL and custom recovery didn't solve the issue, but going back to JB (either full stock, or unlocked BL with CWM) totally cured it. The most bizarre thing is that it started out of nowhere, as I didn't do anything to my phone recently, apart from installing some apps here and there...