Default Change baseband on stock 4.3

Hello all


I searched a lot, but i havent had any responses.

I installed the new 4.3 stock firmware, everything was fine. The thing is im having an unusual battery drain when on mobile network, the phone is changing constantly between 3G and HSPA and i think this is the cause for the drain.

I guess flashing my country's baseband via ODIN will solve my problem but i do care about warranty.

Due to that, i want to know if flashing a 4.1.2 baseband via odia over my 4.3 stock germany will trigger the knox flag. If anyone who had tried this could answer that i would be glad

And another question, when the stock firmware for my country is available, will i be able to flash it via odin and it doesnt blow the knox flag?
Samsung Galaxy Ace - CyanogenMod 10.1.3 by androidARMv6
LG Optimus L9 P768 - LG stock 4.1.2, rooted, LOCKED bootloader
Samsung Galaxy SIII i9305T - Stock 4.3 Rooted, Wanam Xposed