Only sure fire fix I know of is to switch to ceramic pads. It could be possible the brake pad shims are squealing. To fix that you just pull the pads and apply a light coat of brake grease with your finger on the part of the pad shim where the pad travels. If thats not the problem you could try changing the way you drive if you dont want to change them to ceramic. For instance if they squeal under light breaking then dont do light breaking. In future stick to ceramic pads to keep from having this kind of issue.