ok... i gotta phone on ebay... it's a SX1_CZ-SK-RETAIL-uk-cz-sk_06_0003

can i get different firmware for it?? or do i have to keep with the stuff i have now?? can i use the UK-RETAIL instead? or international-RETAIL?

also... what is the best firmware version to date? and where can i get it?

and it says i have version 12 on my phone now(i've only had it for a month or so) and i wanna downgrade... so where can i get the stuff to do this? help me out please!