First of all...check your SELinux status.
Is it on permissive or enforcing status..?

Then if you root your phone..the Knox warranty flag will go 0x1 and it's unresetable.
The rest is pretty straight forward..you can flash custom or stock ROM but not any downgrade.

Yes..should be okay for rooting. But flashing different kernel or custom recovery sometimes bring problem. I sofbricked my phone twice and need to go to service centre.

Safest way is either you root and stay on stock rooted ROM or flash custom ROM and use it without tweaking anything else.

Look at that custom ROM thread and follow each and every step.
Then you should be okay. If that custom ROM need to be flash via CWM then use CWM and not TWRP or Philz. Like I said..follow each step carefully to avoid any problem.

Good luck to you

Forget bout S3 flashing...with SELinux and Knox combo..everything changed. Using different custom recovery can get your phone into bootloop.

Root phone then pick which custom ROM you want. If that custom rom state use CWM then only you flash CWM. After flash and install CWM..do Nandroid backup first..then proceed with flashing that custom ROM.

But i tried to remove it but failed. How u guys do it? Using fingernails?

You jog everyday ke ?
Btw,

http://www.trustedreviews.com/news/samsung...ry-replacements

Good job Samsung

Depends on the firmware itself. Some firmware come without wipe but there are some firmware that wipe clean your phone.

That's why we need to do backup before doing any flashing.
But for upgrading firmware...better do a clean flashing to avoid any FC problem later on.

<insert Users>
ahodil edwincodec n guys...
sorry for long long wait..

actually i went to Kuantan for 2 days vacations

[ehem]
i flashed the leaked 4.3

Camera, dah yelling long time and fixed...
and adding some useless features on S4
and added Knox security apps [when u opened and TRY TO do not install it, otherwise u gotta to downgrade your firmware, n as abang Wave mention, your Knox flag'll triggered to 0x1 ]

yes sire..
and before that, i backup my data w Helium apps , just flashed it via Odin [1st 4.3 Firmware is comes from Holland]

9505

and the firmware is Holland , friend give me the link to download it

lol...!

why go flashed leaked EMJ5? i flash Germany ROM pon no issue till now arh.. 

[PS:on-da-way downloading ParanoidAndroid V3.99 rom ]

Just a quick check, my handset is from Malaysia but currently in South Korea ... do you think i will get faster updates there ?? LOL ... havent see any updates yet though ... =.=

I believe updates are based on our firmwares. .no..?
If we use M'sian firmware...we receive M'sian OTA only..not Korean or any other countries OTA.

You can receive OTA using other country simcard...but you be receiving M'sian OTA...not Aussie OTA. Otherwise you gonna brick your phone lor 

OTA is not  a full firmware...sortta receive whatever new or patching only. That's why the OTA size is small compared to full firmware.

If you flash other country firmware..that's okay as you flash full firmware hence changing the whole phone system...
You can still flashing certain part such as modem..kernel..etc

Make a full backup first lar...just in case it's a wipe firmware.
If you're rooted..use Titanium Backup.
If not rooted...try Helium backup.