Unfortunately the process com.android.phone has stopped in CM 13

I have a good old nexus 4 still trying to keep up with the big boys in the market. After google ditched the plans of releasing the latest android 6.0 - Marshmallow for nexus 4, things didn't look so great. But with the release of CM 13 (mako), even nexus 4 has android 6.0! Previously, I was running CM 12.1 and I dirty flashed CM 13 on top of it. Although it doesn't have all the features that CM 12 had, with time, the awesome guys in XDA and cyanogen will port all the features to CM 13.

After dirty flashing CM 13 on top of CM 12.1, I faced some problems. First of all, things were kinda slow. So I went to Developer options in Settings and set all the Animation scaling to .5x. This considerable made things faster. Secondly and more importantly, my sim card was not getting detected and I was getting a ton loads of popups saying "Unfortunately the process com.android.phone has stopped".

I looked at the logcat to see what is going wrong and I found that this was appearing a lot of times.

Clearly, the problem was with com.android.providers.telephony. Upon looking closely, the problem was related to CursorWindow and Cursor. Hence, the problem was not with CM 13 but with the old database left behind by CM 12.1. 

Solution

Just delete the folders /data/data/com.android.providers.telephony and /data/data/com.android.phone using some tool like Root Explorer or you can do this in adb shell.

rm -rf /data/data/com.android.providers.telephony

rm -rf /data/data/com.android.phone

Then, restart the phone.

Add Exchange account to Gmail 5.0 on older android versions

I installed unofficial CM 12 with Android 5.0.2 today. Earlier I was using stock Android Lollipop and it had the option of adding Microsoft Exchange account. Unfortunately CM12 didn't seem to have it.

After doing some research I figured out that only devices running stock Android 5.0+ are capable of having exchange accounts. And CM12 although runs on Android 5.0, doesn't have this feature. On doing further research I found out that Android 5.0+ have something called Exchange services which enables gmail 5.0 to handle exchange accounts.

Download Exchange Services

Then, install and restart your device. Walah! Gmail will be able to add exchange accounts!

Note: This method is not just for CM

Android L theme on Cyanogenmod 11

After Google announced that the new Material Design is going to be adopted on Android's next release, currently codenamed Android L; lot of us have wanted to try it. Unfortunately it (dev version) is available only for nexus 5 and 7.  Thankfully there is Android L theme by tung91 on google play which brings near Android L experience to other users.

You can try Android L or Android L Dark.
This is how it looks like on my nexus 4:

Google Calendar sync fails after deleting stock calendar app in CM11

I installed CM11 on my Nexus 4. After I installed Google Calendar, I thought deleting stock AOSP calendar app and few other depending apps wont hurt. Unfortunately Google calendar sync stopped working after that. "Calendars to display" was empty and "Calendars to sync" never completed loading. When I searched for solution for this online, people suggested to do a reset; which I didn't want to do. So I tried reinstalling the default AOSP calendar app. It fixed the problem!!!

Download the following apks and install them on your phone.

GoogleCalendarSyncAdapter.apk
SecCalendar.apk
SecCalendarProvider.apk

Update
Some people say that they face the following error while signing in.

"Couldn't sign in. There was a problem communicating with Google servers. Try again later"

After installing the above apks, if you open the calendar app directly you will get this error. You have to restart the phone to fix it.