[T-Mobile Samsung Galaxy Note 3] MasterSe7en:
Okie, so I wrote this guide up for someone in another post, and a few people said it was very helpful so i hope it can get stickied here.

Also i know this information is All over the place :D but it was a bit scattered for me, but id like to post it here in my Fellow N900T Owners section :D

I'll give a brief explanation in the differences. The Colors of the titles indicate how safe/dangerous it is to modify one of these things and wether it will void your warranty,

Green

=Wont void your warranty, and easily reversible.

Orange

=Void Warranty, Reversible, But starting to get Dangerous,

Red

=Definitely Voids Warranty, and if screwed up, could ruin/brick your device Definitely Voids Warranty, and if screwed up, could ruin/brick your device

Rooting:

When you are rooting your device, you are basically forcing your stock version of android to allow you (the user) root access, therefore allowing you to bypass/allow signature verification for apps, now this could be anything from homebrew apps that you are making yourself...to the naughty pirated apps, and i don't encourage the latter. Rooting your phone does

NOT

void your warranty, you can always UNROOT. By giving yourself root access to your phone, your allowing the next to happen:

Flashing a Custom Recovery:

Ok ill explain this as simple as i can...Mostly all if not ALL android phones have a stock recovery, this is a safeguard in case some kind of software fault happened in the phone(stock software fault or what have you). Flashing a custom recovery would be your next step after Rooting a device (IF) you want to go further than apps, meaning Kernels, Roms etc. Now the reason you must Root your device in order to install a custom recovery, is because like explained above signature verification....Now this is when you begin to tread in warranty territory, once flashing a custom recovery...your warranty has become

VOID

, however what the custom recovery allows you to do is a multitude of things, but the most major is Flashing .ZIP files, which most roms are in the form of, now not only Roms are in ZIP files, so are kernels,mods,baseband firmwares, etc, with that being said, different phones/devices use different methods of flashing roms, lets say for example you somehow screwed something up on a samsung really bad, and it wont boot, however, you can still get into download mode...then you're safe, because samsung uses Odin to flash the entire phone back to stock meaning Recovery/aBoot/Data/System and bring you right back, but if you hard brick it, theres only 3 ways out from that...and they all suck....number one, is call me and send it to me to Jtag it for you ..but it takes long and its not that cheap, #2, Desolder the chip (whichever it is on the device that has caused the problem) and replace it...and thats not an easy task at all, ive done it once to an S3 successfully, after that i never wanted to do it again, and this was back when they were really expensive, and lastly....#3.....and this one is the worse....go buy a new one SO BE CAREFUL!

ROMS:

So now that we have a custom recovery, a rom is basically a heavily modified version of Android! and let me tell ya, i love them...i love so many of them, there are sooo many different things that you can do with roms, but the most desired from what ive gathered, is so people can remove the bloatware that comes with their phone when they buy it from the carrier/manufacturer. Thats not all tho, there is way too much to get into, but some roms allow you to Overclock your phones CPU/GPU, and change the Behaviors of the phones hardware, and the major component in roms that allows that is the Kernel.

Kernel:

Now dont totally quote me here, im still learning kernels, but a kernel is basically the binary software in the phone, almost like a bios that when modified from stock, changes the behavior of MOST of the hardware, not all. Now i could be wrong and anyone please feel free to correct me, now i do want to give you a shot of my own advice here...if you dont know what you are doing, kernels are dangerous to a noobie..before i started messing with roms and kernels, i tried to get the best understanding i could, and ill be honest with you, i blew up a couple S3's doing so. but im still learning. so if you're unweary or still not educated enough in the hobby to get to it, please read more up on it, because as none of these guys here that are devs nor people like myself that are trying to help intend to destroy your device on you, so please be careful for your own device's safety, and to save yourself money and a broken heart.

Knox:

Ok now correct me if im wrong here, because im still learning as this is new to me, i only saw it on the MJA bootloader on the S4 on Jellybean from Sprint when they first OTA'd it, but knox looks to be Samsungs pathetic try of not lettings us Access the devices binary software, like an encryption, or to only let us access and modify certain things, also samsung has added a flash counter, which will tell them how many times you have flashed a new rom, once the knox counter is tripped....your warranty with samsung is gone, if youre lucky and you bring the phone into a local carrier store, theres a good chance the guys working there will have no idea how to even see if, from what ive learned you must be in download mode to directly see the knox counter.

I Hope this helped and shed some light on some information, and please if anyone has anything to add or to correct me if im wrong anywhere please do so ^_^

P.S. To be totally honest, theres always a way to restore your device and even get the flash counter back to 0 again and put everything back to normal, if an experienced tech looks at it and puts it in download mode unless all is restored, hell be able to see everything, but honestly, if you pay off the phone, you havve nothing to worry about, but then again, i dont care much for warranties, so it all depends on how savvy with fixing problems when they go wrong, but if you ever need i can help you, im pretty experienced when it comes to everything but developing atm, i was a microelectronics major in college, so my expertise is mainly in hardware i.e. if you hard/soft brick the devvice i can usually get it out of that.

please excuse my typing, i type extremely fast, and i have a mechanical keyboard and i think some lettings are startings to give way such as the V key.

So this is what i came up with ^_^ i hope this helps and please feel free to correct me or Add to this by commenting in the posts below and ill change the write up as needed :D

Hope this heellppsss :D

Questions please :D

Update: 2/17 Thanks for the Knox info towle! gonna add it :)