Although many countermeasures have been developed for desktop and server environments, buffer overflows still pose a big threat. The same approach can be used to target mobile devices. Unfortunately, they place more severe limitations on countermeasures. Not only are the performance requirements at least as important, memory and power consumption need to be considered as well. Moreover, processors used in mobile devices generally are equipped with a different instruction set. Therefore countermeasures may not be ported easily. Multistack is an effective countermeasure against stack-based buffer overflows. It protects applications by using multiple stacks to separate possible attack targets from possible sources. However, its performance overhead will no longer be negligible on the ARMv7 platform (widely used on mobile devices) and it wastes too much memory, making it too costly for mobile applications. We propose 3 methods to reduce memory overhead up to 28% with only a 3.91% performance overhead.