I posted a question few days ago and I still have the doubt: my post.
Now the same "exit signal Illegal instruction (4)" error happens when I play with the "findFirst" of Tutorial 2 INVO; in "$this->session->get('auth')" the "id" is a string, when "findFirst" is getting the string it generates the error. Why is it happening? is there any documentation i can read? any solution (beside making it the "safe" build)?