Resolve battery drainage problem after Marshmallow update on android device.

☞If you have problems with your Android device including the dreaded Black Screen of Death you may be told to WIPE THE CACHE PARTITION.  On a Samsung Galaxy A8 or S6, you can do this by:

1.Powering off the device

2.Press the VOLUME UP + HOME  + POWER buttons all the same time and HOLD THEM DOWN

3.Release only the POWER button when the device vibrates

4.Release the other buttons when the ANDROID SYSTEM RECOVERY screen appears

5.Using the VOLUME DOWN / UP buttons to navigate, select WIPE CACHE PARTITION

6.Press the POWER button, which will act the ENTER key on your keyboard

7.You will likely see some progress notes (at the bottom of the screen in small print) and after about 20 seconds it will likely show DONE

8.You can then reboot the device and see if your problems are fixed

On some Android devices you can clear the cache through the typical user interface:

☞SETTINGS
☞APP MANAGER
☞LAUNCHER
☞CLEAR DATA, CLEAR CACHE

You may ask yourself, what does clearing the cache on my cell/tablet actually do? 

♯The cache partition contains most of the temporary files, logs and remembered bits from the various applications on your Android device.  They can also be left over files from before your last Android update.  If that happens your device could be trying to use stored files that are not meant for your current version of Android.  Think of it the same way you think of your browser cache.  Just like a browser cache, sometimes those stored bits cause more problem than they solve and so it is a good idea to delete the cache periodically.

♯Wiping the cache will NOT delete your apps or your data or your configuration.  It will simply delete the temporary junk.

This can resolve MANY problems:

✔Black Screen of Death (BSoD)
✔Slow performance of apps
✔Lag in the User Interface
✔Apparently random errors and failures

On a related note, there main cache should not be confused with the DALVIK CACHE.

♯When your phone starts up, the Dalvik Virtual Machine looks at all your APPS and frameworks, and creates a tree of dependencies which is stored in the dalvik-cache. This allows applications to run in an optimised state (and explains why your phone takes longer to boot up after applying a new rom, it’s rebuilding the cache.)

♯the /data/dalvik-cache directory that can be found on typical Android devices. When you install an application on Android, it performs some modifications and optimizations on that application’s dex file (the file that contains all the dalvik bytecode for the application). It then caches the resulting odex (optimized dex) file in the /data/dalvik-cache directory, so that it doesn’t have to perform the optimization process every time it loads an application.

CREDIT: www.ddsystems.com.au/other/android-2/android/

♯Deleting the DALVIK CACHE will slow your Android devices boot up and application speed; this is not good.

♯If you are wondering about the CACHE partition, wonder no more:

♯/cache partition is mostly for saving the downloads from Google Play Store, found in /cache/downloads. It also can hold the recovery log found in /cache/recovery called last_log as well (this holds any errors and/or diagnostics from the recovery binary a la CWM or stock, which will get logged in the file to aid debugging and development of the recovery binary).

♯There is also another directory in there called lost+found which holds any recovered files (if any) as a result of file-system corruption, such as incorrectly removing the SDcard without un-mounting it.

So really, there is no loss of data from clearing it.

In fact, upon Android boot-up, the script will clear out the /cache/downloads to make way for any new downloads/updates from Google Play Store.

CREDIT: forums.androidcentral.com/droid-razr/343560-what-exactly-wipe-cache-partition.html

☞Take note that because the CACHE PARTITION is just that, a separate partition, you will not see your FREE SPACE increase after you delete the content.

I hope this helps resolve your problems, but if not you may find techrez.com/fix-samsung-galaxy-s6-black-screen/ and gadgetguideonline.com/galaxys6/samsung-galaxy-s6-guides/how-to-boot-into-galaxy-s6-recovery-mode/ helpful .

Thanks..