This light steel shield is specially crafted with a series of straps to allow a character proficient in shields to ready or stow it on her back quickly and easily. If you have a base attack bonus of +1 or higher, you may don or put away a quickdraw shield as a swift action combined with a regular move. If you have the Two-Weapon Fighting feat, you can draw a light or onehanded weapon with one hand and a quickdraw shield with the other in the time it would normally take you to draw one weapon. If you have the Quick Draw feat, you may don or put away a quickdraw shield as a free action.
律规则专业点，原文第一句没说放回背上是个自由动作。后面讲动作的才是规则文本
Put away不是放回背上
就是说，你本来要2个移动动作才能装背，现在只要一个啦
惊了。先抱歉。这么看原文并没有提到什么放到背上，先承认一波错误。
不过这里我又有一个问题，和这个话题有关。
1. 正常的盾牌，BAB至少有1时，可以使用“和移动动作同时进行的的自由动作”准备或卸下任何盾牌。与此同时，取出盾牌需要一个移动动作。
准备或卸下盾牌：将盾牌在你的前臂上装紧握住，你才能获得盾牌给予的AC加值，你也可以将盾牌卸下抛掉，以空出一只手来进行其他行动。如果你的BAB为+1或更高，你也可以在进行移动的同时以一个自由动作准备或卸下盾牌。取下（但不装备）盾牌是一个自由动作。
Strapping a shield to your arm to gain its shield bonus to your AC, or unstrapping and dropping a shield so you can use your shield hand for another purpose, requires a move action. If you have a base attack bonus of +1 or higher, you can ready or drop a shield as a free action combined with a regular move. Dropping a carried (but not worn) shield is a free action.
2. 参考你找的原文，假设Put away指的只是装卸盾牌而不是指的把盾牌收起来的话，原文可以这么理解：
快速装卸盾牌，BAB至少有1时，可以使用“和移动动作同时进行的的迅捷动作”准备或卸下任何盾牌。与此同时，取出盾牌需要一个移动动作。
This light steel shield is specially crafted with a series of straps to allow a character proficient in shields to ready or stow it on her back quickly and easily. If you have a base attack bonus of +1 or higher, you may don or put away a quickdraw shield as a swift action combined with a regular move. If you have the Two-Weapon Fighting feat, you can draw a light or onehanded weapon with one hand and a quickdraw shield with the other in the time it would normally take you to draw one weapon. If you have the Quick Draw feat, you may don or put away a quickdraw shield as a free action.
结论岂不是，使用了快速装卸盾牌，反而比正常盾牌需要更多的动作装卸？