[Galaxy Tab S Android Development] StiiLe:
Done ! Thanks again Ashyx, I feel stupid... my only mistake was... not waiting enough ! :/

Here is my method, if it can helps someone else, based on Ashyx' big work. It's a first time for me with Odin/FlashFire/etc., I usually use TWRP (Nexus etc.). Notice that I did too much nonsense things, but I explain it anyway. I think if you just read Ashyx' method, it's enough.

I bought a Tab S 10.5 LTE (SM-T805) on Amazon.it in August 2015. I got it with Stock Lollipop 5.02 and I wanted the IronRom 2.3.5 but without triping Knox.

1.) On your Windows computer, install :

- Samsung's USB Drivers

- Odin v10.0

- Adb Setup 1.4.2

2.) On your External SD-Card, put :

- KingRoot v4.1

- SuperSuMe v6.7

- FlashFire v0.20

- IronRom v2.3.5 for T805, with your Tab S or Tab A apps inside (read 1st post).

3.) Download some firmware to be ready :

- Kitkat Firmware : T805XXU1ANF8_T805OJV1ANF3_T805XXU1ANF5_HOME.tar.md5

- Lollipop Firmware : T805XXU1BOCC_T805XEF1BOC1_T805XXU1BOC1_HOME.tar.md5

- Lollipop Bootloader : T805XXU1BOCC_T805OXA1BOC4_DBT Thanks to Nick Noctem

4.)Downgrade.

This step may be useless because I thought that we could not root on Lollipop. Boot in the Download Mode (Power + Home + Vol-), downgrade back to Kitkat Firmware with Odin (put your file in "AP", plug your Tab S, start, done). You may have to wipe user data / cache in recovery (Power + Home + Vol+).

5.) Root.

Install KingRoot, launch it (it mays restart the tab), then install SuperSuMe and launch it (it mays restart the tab too). This last app will replace KingUser by SU, and deleted all files related to KingUser. (The other method was not working for me). You're rooted on stock KitKat.

6.) Upgrade.

Boot in Download Mode, and upgrade to your Lollipop Firmware with Odin. You will be with a stock Lollipop rooted ROM.

7.) Install IronROM.

I understood that we have to flash only stock bootloader to keep Knox 0x0.

- IronRom needs Lollipop bootloader.

- Only Odin can flash stock bootloader, FlashFire can't do that.

- I guess that I was already with a Lollipop bootloader (step 6) as I flashed the stock firmware included bootloader. But I did so much nonsense things to understand my mistake, that I flashed again the Lollipop bootloader from Nick Noctem with Odin here... just in case.

Then, install FlashFire, launch it, give it SU's rights. Click on the "+" on the bottom-right corner, click on "Flash Zip or OTA", select your IronRom.zip. You can click on the "Reboot" part, and choose "Recovery". Flash it.

8.) The end.

At the end, it will restart in recovery mode... or not. Mine was stuck on a black screen. I had to reboot it, and wait for 10 mins. That's important to wait ( :silly: ) : I didn't and I thought that it was not installed correctly, then I did this method 3-4 times just because of this. :o :o :o

It boots, wipe userdata to avoid FC.

9.) Root.

I lost root with IronRom. As told page 46, I just installed SuperSU v2.49 BETA over the existing SuperSU and it worked again.

There is still something strange, I can't enter in the recovery mode (when I choose reboot into it, or when I Power+Home+Vol(+)). Anyway, no time to do more, I'll try to put a dark theme, if it's possible and if I do it fast. :)

(Thank you again Ashyx, and Nick too).