Bad proximity sensor

[greedo_greedy]

The $99 deal from Microsoft is quite tempting indeed.

Just have a question, I know this software issue is bothersome but is it really that bad that it will make me want to not use it? I mean it should still function and provide me with basic calls and texts right?

Or is it really experience breaking that it will make me toss the phone at the pavement?

 

[gvp 1995]

After weeks of researching this issue, it looks I am finally approaching the understanding how this bug works, and more importantly - the solution.

It is not binary works/does not work. There are 3 distinct modes of the Proximity Sensor on this phone.
1. Sensitive
2. Not sensitive
3. Not working.
I don't know how it is done on other phones, but here it looks they wanted to make PS respond depending on the proximity to the surface (maybe for double tap to wake?).

The first mode engages when the phone is face up - no surface. When the call starts it is enough to bring the hand and the screen is off.

The second mode (semi-sensitive) can be reproduced if the phone with no case put in the pocket or face down on the soft surface (furniture or something). Then brining the hand is not enough, but PS still turns off the screen if brought close to the ear.

The third mode (non-working) can be reproduced if the phone with no case put face down on the hard surface - wooden desk in my case. Then, upon answering, there is no way the screen is off, no matter how close you bring the phone to your ear.

In the process of these experiments, I collected 5 different cases. Some of them make it not working - for example, the one with the cover. To cut the long story short, there is one case CoverOn that serves both purposes: when the phone is face down on the hard surface, the case has enough ridge to trigger mode 2. At the same time the ridge is not big enough, so you can bring the phone close to your ear enough for PS to work.

So finally I do have a working phone, and I love it. The only one question remains if you get these 3 modes automatically. What I mean by that is that there are several things that are involved - signing in, installing updates, updating apps, restoring the backup, etc. that could be done in a different order. After the numerous attempts that failed, I developed this sequence to set up the phone, and I don't know if it is important or not, but it did work for me:
1. Reset the phone with WSRT with no SIM
2. Turn off automatic updates before connecting to WiFi
3. Turn WiFi on
4. Sign In with MS account, don't restore any updates
5. Update all apps in the store (Store -> Check for updates)
6. Insert SIM
7. Install all the OS updates one after another (4 in my case)

I was using unlocked phone but restored a T-Mobile image, which gave me WiFi calling

 

[gvp 1995]

All I wrote is correct. But it works on a flat surface. As soon as you put the phone in the pocket (not any pocket, but mostly), it still miss-behaves.

Here is the WORKAROUND. In the situation you know the proximity sensor will not work, before pressing 'Answer', briefly press 'Power' twice. After this press 'Answer'.