pathfinder – How to avoid shield penalties?

Buckler:

Advantage: […] You can also use your shield arm to wield a weapon (whether you use a casual weapon or using your hand to help handle a two-handed weapon), but you incur a -1 penalty on throws. attack. This penalty is cumulative with those that can apply to fight with his left hand and to fight with two weapons. […]

Is there a way to avoid this penalty of -1? I've searched the web and found nothing, but maybe I'm missing something. Could be an exploit, or perhaps a magic object?