SGH-M919 Updating / Rooting

[filter4ever]

I am a newbie to GSM, so bear with me

T-Mobile is offering me an OTA update to M919UVUFOK3 every 24 hours. Is it too late already to keep EFuses from blowing, since KNOX came with the MK2 on my motherboard? In which case have I got nothing to lose by accepting the OTA update? This would be the most stable, OR

Should I root the MK2, install TWRP, and upgrade via ODIN? I'm not sure if they have OK3 for modded firmware yet, at the moment, all I want to do is upgrade to the latest, most stable firmware / kernel / modem I can while keeping as many E-Fuses intact (knox bit, anything that keeps me from being able to downgrade, root, install a custom ROM, or ressurect my device if it becomes hard-bricked.

Here's what I know about my S4

About Device:

Model Number
SGH-M919

Android Version
4.3

Baseband version
M919UVUEMK2

Kernel version
3.4.0-2015522
se.infra@R0210-07 #1
Sat Nov 16 14:22:56 KST 2013

Build number
JSS15J.M919UVUEMK2

SELinux status
Enforcing
SEPF_SGH-M919_4.3_0010

Secure boot status
Type: Samsung

Here's what I have observed about my phone so far:

* T-Mobile finally gave me a SIM card that works
* Full eMMC dump using RIFF (anything available upon request)
* KNOX is installed
* ODEX information was found on this phone when I looked through partitions in a hex editor
* Found code amongst the boot loader partition in WinHEX, "BootLoader.Rollback.BlowFuse" <<< NOT Warm and Fuzzy feeling

So, in short, do I have nothing to lose by accepting the OTA update (I believe it is still rootable), OR should I root my current firmware and do everything by hand? OTA would ensure greatest stability, but I still want it to be MY phone. Any suggestions?

If anyone wants my full eMMC dump, *.pit file, anything let me know (as long as it's not something personal like a certificate or IMEI)

[filter4ever]

I decided to root the MK2, install TWRP, and a stock (but Knox-free, deodexed, permissive kernel) and flashed the modem, using Odin, version M919UVUFNH7. This ended setting the "Recovery" and "Kernel" eFuses - I guess it's already too late since Knox was installed. Oh well.

A couple questions regarding my RIFF dump though. The resurector DLL has only 2 kernels listed for the M919, I believe MK2 is one, and the first one (4.2.2) is another. Will the resurrector work still? As far as I know, the only thing changed were "Warranty Bits" - Kernel and Recovery, everything else is untouched.

I made a backup in TWRP of my M919 (Boot and System), but I don't know if this is good enough. Can I still flash my MK2 back to the phone and use it? Or will I need to solder again / dump full flash?

If anyone needs a MK2 *.pit, *.riffpkg partitioning scheme, full flash dump (*.bin or *.riffpkg) bootloader whatever for the M919 let me know.

[filter4ever]

I guess it's called "qFuses" for Qualcomm. Same thing though. It makes me sick they would go THAT far just to control how I use my device (OK I can see for the security of the carrier, samsung network, google, or to prevent app piracy - but to write your own apps, or run unsigned (I'm not as rich as Gate's, I can't afford for Sammy to sign my little projects, if they would anyway))

[Spagman]

The MK2 dll for the M919 will still work for your phone.

You customized your phone with a Rom... Roms don't have bootloaders so you are running bootloader MK2 with NH7 system files .

Yes, you can use the TWRP backup you made because the bootloaders are the same...
But you can also just flash back MK2 using Odin and your back in business.