[Galaxy Note II Q&A, Help & Troubleshooting] absinthesummer:
Ok...

You already know what a rom is. A kernel is a lower-level base. It controls the hardware. So when you do something on the interface, in the rom, it tells the hardware how to react. (Ie if you're playing music it tells which speakers to play and how loudly). The kernel controls almost everything you can't see, it relates to performance. Most stock kernels can be limiting as they underclock the cpu by a certain percentage. Because of this, people seek out custom kernels to max out their device's potential. Louder speakers, faster cpu, better graphics, etc. This is all stuff the kernel can optimize... but because you can change so many factors there is a risk of instability if you push your device too hard (max performance) or limit it too much (max battery saving).

Recovery is exactly what it sounds like. When you boot your device the very first screen that pops up is the bootloader. It's giving you time to boot in 3 different modes. The first mode, by doing nothing, is a normal boot into the rom/OS. The second mode, which you get to by one button combination, takes you to recovery. The stock recovery is very limited. It gives you the option to factory restore, wipe cache, update, or boot normally. Stock recovery only exists for emergencies, if your phone fails to boot normally. We have custom recoveries so we can do more stuff, flash custom roms and tinker with things. The third mode is download mode/Odin mode. This is the bootloader interface itself. It's the last resort for recovery if your recovery has been damaged or corrupted. It allows you to connect to Odin or kies and perform an emergency recovery of the device. If you damage your bootloader, your device is completely bricked.

So the order of operation is this:

Lowest level- bootloader

Second level- recovery

Third level- kernel

Fourth level- rom

Bloatware is all the pre-installed apps that your carrier adds to your phone. Most people don't use it, don't like it, and don't want it. That why we root. Without root we basically are just guest users of the device. With root we become the administrators of the device. Until you root, your carrier has admin rights over your phone (to use windows terms).

When you receive an ota update, your carrier can make it to where the update won't proceed if their pre-installed apps have been removed (although this isn't always the case). Additionally, the update package itself checks the integrity of the device. It checks recovery, kernel, and rom. If any have been altered, it will not proceed because it could cause conflict and potentially brick your device. That's why those things have to be stock.

Ota root keeper is simply an app that backs up your superuser rights before an update and restores them after its done.

You should be able to find plenty of roms with S5 features. I'm using one that makes my device fully like an S5 (my device even thinks it is an S5 and every app identifies it as such) I can think of at least 2 others as well. There's plenty to choose from, and if you see a rom you like but it's mudding a particular feature, you can probably find that feature as a stand-alone installation in the forum's themes & apps section. Just about every feature of S5, S4, and note 3 has been ported to this device, so look around!

Also, for future reference, if someone helps you on the forum, hit the thanks button instead of saying it. I don't mind either way, but some people get annoyed and will stop helping them if they don't hit that button lol. It's silly, but it's part of "forum decorum" ;)

---------- Post added at 12:54 AM ---------- Previous post was at 12:44 AM ----------

You're fine, I don't mind answering your questions. Yes, you can unroot fully in the way you just mentioned but you don't even have to go through all the trouble of factory reset. Just unroot in the app. The app can be uninstalled afterwards via the play store.

You can factory reset either way, the same commands are given no matter which way you go about it. But it can be more efficient to do it from recovery because when you do it from the rom it has to create a wipe script for when it reboots, and it has to shut down the rom first. If you do it from recovery it doesn't have to anything, the rom isn't running and it can execute the wipe command immediately. (The wipe command is wipe /data /cache etc)