Wondering if i can debloat some google apps from unrooted lg phone for my father? My father being older does not want to modify his phone, however he has a LG L70 and no sd card, and doesn't use some unnecessary Google apps, such as play, books, and whatever else. My question is can i boot it into fastboot and run a custom written shell script(i run linux ubuntu), which would run something like fastboot oem append-cmdline "androidboot.unlocked_kernel=true"? Which i found on amazon fire 5.1.1 thread on xda-developers forums, then fasboot continue, and in turn, at least on the fire, allows to access the adb shell as root without running su. Then from there run adb shell "pm uninstall {app_name}"?
You're looking in wrong direction. insufficient-memory error shows up when you're running low in space under data partition (named: userdata; mounted at /data). It stores user installed apps (APKs), updated system apps (APKs), their data files inter alia. System apps by-default are stored in system partition (named: system; mounted at /system). That partition is not mounted in read-write (rw) mode and doesn't cause that error. 

Removing the system apps wouldn't achieve anything since as I said, unless the system app is updated by the user, the APK would only reside in system partition. However, it would consume a bit of space to store its data files in data partition. 

If that amount concerns you, then go to  Settings &rarr; Apps &rarr; All apps &rarr; your system app &rarr; Force Stop &rarr; Uninstall Updates (if any) &rarr; Clear data &rarr; Disable. This would:


disable the system app which simply means that you wouldn't be able to use it or update it unless you enable the app. 
delete its data files from data partition since you used "Clear data" button. If it was updated by user, its APK would be removed from data partition as well. 


Why bother with extreme measures then?

Just so you know, adb shell pm uninstall  would blatantly fail to remove a system app, regardless of whether it is running with superuser privilege. 

That said, some system apps wouldn't give you disable or clear data option. But if they are not giving such option then assume that your OEM considers that the app is critical for the stability or functionality of your OS (even if it is not) and you should ignore disabling it. 

If you can't ignore it and wants to take a risk, use this command:

adb shell pm block PACKAGE # for KitKat
adb shell pm hide PACKAGE  # for Lollipop


This would effectively bar that system app from being used even if it causes instability to the system. This also means that the app would never be updated again unless you revert the changes.

To unblock or unhide the app, do

adb shell pm unblock PACKAGE # for KitKat 
adb shell pm unhide PACKAGE  # for Lollipop


PACKAGE &rarr; package name of your system or user app. To know the package name of an app:


for KitKat - follow View app&#39;s full package name? 
for Lollipop - open Settings &rarr; Apps &rarr; All apps &rarr;  your app &rarr; click here


Save yourself all the trouble: "i keep telling him to get one but... and i dont have an extra!" -- save some money, buy an SD card, plug it in his phone when he's not around and there you go with the surprise gift.