Majority of the time your reference is only used if your job requires some sort of high level clearance. Also if your past job is in a different field then your references are pretty much useless.
Wether or not your state law says you can or cant give a bad review, the most common question asked and only one that matters is 'would you hire them back'
Anything else they are told can be fought as slander and HR departments know that.
Other then that - clear the air with your old boss, for your personal mind health it may feel good. Unless you stole from him or killed his dog I highly doubt hes gonna blast you to a new job prospect. Expecially if hes in a management position, he knows the risk with what he says.
Wether or not your state law says you can or cant give a bad review, the most common question asked and only one that matters is 'would you hire them back'
Anything else they are told can be fought as slander and HR departments know that.
Other then that - clear the air with your old boss, for your personal mind health it may feel good. Unless you stole from him or killed his dog I highly doubt hes gonna blast you to a new job prospect. Expecially if hes in a management position, he knows the risk with what he says.