Hacking JPN pokemon ORAS on US 3DS wont accept the serial code

[aos10]

so , there is special code for Pokemon ORAS only in japan

if you enter POKEMON497 in mystery gift you should get HA Serperior
of course this will notwork on US/EU games

so , i downloaded the JPN version of Pokemon AS ( 3DZ and cia )
they both are updated to 1.2

i manged to get the shiny beldum , so i can be sure the mystery gift should be work

tried the special code "POKEMON497" and i get nothing
this message appears
"the gift was not there..."

i think those codes only work on japanese 3DS only , not just the game

the internet wifi will work however

is there a way to change the 3DS region ?