[Q] can i go back to official 4.1.2 after updating it to pre-release 4.2.2

i updated my Galaxy S3 to 4.2.2 pre-release(from sammobile) using Odin. it works fine but the multi window feature+lock screen widgets and apps are not working.. i tried re-flashing the phone after wiping cache but still problem is there.. my questions are
1) how can i fix the issues?
2) is it OK if i re-flash the phone with official 4.1.2 firmware(downgrading) using odin?