I have found out how a pkx is shiny, it uses offset 0x18-0x1B (I'm not sure how the game generates it but acts as a unsigned integer for shiny check), ID and SID
Like the PID in Gen 5, divide this seed into 16 bit parts, let s1 be the upper part and s2 the lower part
If (id^sid^s1^s2)<=8 then...