[General Questions and Answers] :
HOW-TO set your launcher (really) persistent

This is a must-have tweak and I hope all of you perform it without problems, you can achieve this in your Android device or in a PC but I am going to explain how to do it in PC because I think is more secure. The post is big because I am detailing things, but the procedure is very simple, you must know how to use adb:

1. We need to copy or adb pull the settings.db file inside /data/data/com.android.providers.settings/databases/. You can connect your phone through USB and "adb pull /data/data/com.android.providers.settings/databases/settings.db" or you can use a root explorer to copy the file into your sdcard. Please keep a copy of this file unmodified and copy as, lets say, settings_mod.db to your PC in the same folder as ADB is installed.

2. We need to know the process name of our launcher. The easiest way I know is through Link2SD (you do not need the partition thing, just need the app). Launch Link2SD, tap on your launcher in the list, a new window will appear with your launcher name in bold font next to your launcher icon, down the launcher name is the process name. For example, my launcher is Nova Launcher and the process name is "com.teslacoilsw.launcher". Similarly, you can go with a root explorer to /data/app/ and the apks will be stored with the process name, in this case, you don't use the "-1" or "-2" part at the end of the name if it has it.

3. Install SQLite Browser to your PC (http://sqlitebrowser.org/) and open the settings_mod.db (step 1) from the just-installed program, click on "browse data" tab, select systemex in the Table list. Find the registry with name "apps_set_oomadj" and edit the value so you can add your launcher's process name. If it had, for example, "com.android.providers.contacts;com.huawei.fastboot", now it should have "com.android.providers.contacts;com.huawei.fastboot;com.teslacoilsw.launcher". Of course, if your launcher is not Nova Launcher, you should modify accordingly.

4. Click on "New Record" button to add a new registry wich will appear as NULL name and NULL value. Edit the NULL name with double click and write down "oomadj.the.process.name", in my case with Nova Launcher is "oomadj.com.teslacoilsw.launcher". After this you need to make a decision, because in NULL value you have to put a number and if you put a:

-1: The launcher is almost unkillable no matter what

0: The launcher is almost unkillable but system will kill it if system or critical apps (like SystemUI or Phone) requires it

1: The launcher is killable if you are using an app which eats RAM as hell (I use this)

2: The launcher is killable but still more persistent than the average app (Huawei Launcher behavior)

MORE THAN 2: Weak ass launcher, as all those launchers we install from the Play Store no matter you use the "persistent" feature they provide.

Once you are done editing settings_mod.db click on the "Write changes" button right downside the menu bar. Exit SQLite Browser.

5. Now is time to put settings_mod.db file back to your phone, remember, you have a backup in case something goes wrong, right? First, connect your phone via USB to your PC and reboot your phone into recovery. Second, use CWM "mounts and storage" menu to "mount /data partition". Third, from your PC write down "adb push settings_mod.db /data/data/com.android.providers.settings/databases/settings.db". Reboot.

SIDE NOTE: From your Android device you can use X-plore file manager to get the settings.db file and to put it back. Also, you can use aSQLiteManager app to modify the settings.db.

SIDE NOTE 2: You can modify almost every process priority in a similar way. If greenify, for example, is being interrupted and it reports it like this, you can use this method to raise greenify's persistance. Or if you need your camera to be always-ready then you can raise its persistence (but don't forget you need to open it first to be persistent because it won't run at boot as a launcher).