[Galaxy Note 3 Themes and Apps] xperiacle:
Let me explain to users what this so called "tweak" is all about.

If you followed [MENTION=3931450]dr.ketan[/MENTION]'s post where he said that he was able to enable emergency mode through some hidden activity in SecSettings, that is true and he also said that once enabled there is no going back except thru factory reset because there is no OFF switch. I had the same issue. I could just use a simple app to enable/disble the switch but because the apk files for UPSM or emergency mode namely EmergencyLauncher.apk, EmergencyModeService.apk and EmergencyProvider.apk (all files from stock S5 Roms) requires apps that trigger them to have system level permissions and no third-party app can call them unless signed with OEM key and have the necessary permissions in the manifest. So the only way to trigger them is if my app is signed with Samsung's key (which is impossible) or use Xposed to get a system level context and trigger them from that context and that is what this "tweak" is done.

What files are included in the tweak? Inside the module is all three files for UPSM or emergency mode - EmergencyLauncher.apk, EmergencyModeService.apk and EmergencyProvider.apk. In the initial setup all three files are copied to /system/app folder and requires a reboot for the system to initialize. After that my app uses xposed and triggers them using exactly the same commands that triggers them in the S5 and the app can do so because thru xposed, the app can get a system level context and the necessary permissions to trigger the mentioned UPSM apps. That is essentially what the module does - in simple terms the module calls EmergencyModeService.apk. After that it is all up to EmergencyModeService to do its background work.

Take note that EmergencyModeService.apk is an original stock S5 system file - no modification except a few resource edits to point them to the correct resource in the Note3 framework-res.apk. What EmergencyModeService.apk does under the hood is exactly what it does in the S5 which includes disabling the wallpaper manager, turning screen to greyscale, disables two cores, kill background tasks and disables all packages except the core ones necessary for basic functions. This is the same reason why all other xposed modules are disabled when turning back to OFF - because xposed installer which I included in the core apps thinks they don't exist when in UPSM mode. After all the background work, EmergencyModeService calls a simple launcher - EmergencyLauncher.apk which provides the GUI and shows the basic shortcuts for dialer, messages, torch, etc.

One issue I encounter when using the original EmergencyLauncher.apk is it uses some code in framework2.jar which the Note3 does not have so it won't run. As I don't want to mod so many framework2.jars I needed to rewrite my own simple launcher combining the features of both UPSM and emergency mode and also it provides me flexibility to do updates on the launcher and design it however I want which works even on S5 roms.

There you have it - a knowledge of what the "tweak" does before you go bashing that it is a "joke". I hope I have satisfied your questions about the "tweak". Whether it works for you is a matter of use case. The first time you enable emergency mode, Samsung shows a disclaimer dialog which you need to accept before proceeding. I recommend YOU READ IT.

As to the benefit of grayscale, well I don't know about your use case but browsing websites which are predominantly on white background makes turning them into grayscale minimize my eye strain. Try browsing on the same amount of time with grayscale ON and grayscale OFF and see if see it consumes the same amount of battery.

And well, if it does not work. You could just say it is just one of those many mods on xda that you have tried but didn't work and MOVE ON.

As for me, I still like modding - it is not the end result of the mod itself but the excitement and the process of it that keeps me going back here on xda. If I stop having FUN, then I will move on.