T805 bad flash in Odin and no recovery with button combo

Hi everyone, some help is needed. Mistakenly when rooting my stock T805 with CF autoroot, tired and sleepy, I flashed it in Odin in BL (bootloader) and not in AP box as I should. Soft bricked it, couldn't go back to stock, somehow managed to install recovery, from there to some AOSP rom and finally to Xtrolite (which is great) .Anyhow, all is working now, EXCEPT, i still cannot flash stock rom in Odin, seems i destroyed bootloader but then again, I flashed stock bootloader-only file, i got recovery, any rom etc. Help is needed what to do??
Also, is this normal that VOL UP+ POWER+ HOME wont enter recovery?? I remember this when i bought it, with knox 0x0 and now also, with TWRP, i have to use an app to reboot to recovery?! weird...

Cheers!

Please help newbie t805

Hi guys

Just bought a t805 and loving it atm. Few questions if anyone can help:

1. its a t805 but its got a octacore 5420 chip does that make a difference if I wnt to install custom recoveries/roms should I install for the t805 or t800?

2. Are there any good roms for battery and speed on the t805 worth flashing?, reason being don't want to trip know if theres nothing better than stock.

3. Any good tips for battery and speed if not?

4. Are there any fast chargers out there that are compatible i.e the charger that comes with the s6?

5. If I root without tripping knox can I get rid of all the bloatware that's installed my rom is T805XXU1BOC1?

6. Finally would love to make use of the sd card for more app installation any way of doing this.

Guys I appreciate that all this info is most probably in the threads but in all honesty came onto this tab quite late so will involve loads of reading and asking loads of questions so any help is really appreciated.

Many thanks
Mav