the problem appear if your lcd is not the original one
solution 1 :
replace lcd with original lcd i9205 or i9200 touch will work normally

solution 2 without changing lcd :

1- Root your mobile (CF-Auto-Root-melius3g-melius3gxx-gti9200.zip) via odin or for i9205 search about the compatible root that it is easy

2- install recovery (philz_touch_6.25.0-melius3gxx.tar.rar) via odin

3- install custom rom i use (Simons_9200_Touchwiz_Rom_v211_based_on_BMJ2.zip) via memory card

also there is custom rom for i9205 from Simons search about it

note important :1- Do not disable knox

2- maybe you need update SU via market

3- as i said some model of copy lcd will not work with solution and keep restart until you remove the touch flex from lcd

i think now it is clear and about downgrade with custom rom it will not brick your phone but i will not take any responsibility

all done and enjoy tongue

also maybe some one can make patch for that problem inspiring from that solution