Android OS High Mobile Data usage

Question

Guys the android OS data usage on mobile data seems to be unusually high..

I have blocked data access for all the apps and whitelisted only a few 4-5 apps in AfWall firewall.. While play store , play services are disabled too..

Also I keep Google sync off when on mobile data and use it only on Wi-Fi..

And one cannot turn off background data on android OS

Settings > Backup and reset is turned off And all the photos backup etc too.

Anything related to Google or backup is turned off in short

The mobile is Moto G first gen and most of the OEM Motorola apps are freezed

So why so much usage by Android OS.. What packages are part of it.

Or how to check what services or packages are using the data and how to disable or freeze them.

Also can post if somebody needs to analyse

1. iptables firewall rules
2. Apps frozen or disabled

Screens:

Also:

• backup is turned off
• sync is turned off
• no OTA updates for a long time
• my normal data usage was ~20MB per month for Android OS

Answer 1

One way to reduce data usage it to turn off Data Roaming. This can be found under Settings > Wireless & Networks > Mobile Networks.