Stuck in a bootloop

[vepar22]

So was going to change ROM on my gt-i9300,i downloaded new ROM went to the custom recovery did factory data reset,cashe particion wipe,then tryed to install new ROM and it says something like detected system blocked(it's not exatly like that).PLEASEEEE HEEEELP

 

[Ali_uae]

I think you should post it on XDA-Developer's forum.

http://forum.xda-developers.com/galaxy-s3