The two main things that you need for mobile Firefox to work is Android 2.0 and newer (which you have) and the cpu on phone/tablet has to be a ARM v7 type of cpu as the old ARM v6 will not work. Unfortunately according to http://en.wikipedia.org/wiki/Kyocera_Zio it uses a ARM11 cpu which is of ARMv6 Architecture. The phone is also called "Sanyo ZIO M6000" which is in the not compatible list at https://wiki.mozilla.org/Mobile/Platforms/Android#System_Requirements There were test builds for the ARM v6 but they were slow and crash prone so Mozilla stopped in mean time. If you do not find it on Android Market then that can also be a indicator the device is not compatible. mobile Firefox can be found at http://www.mozilla.com/en-US/m/ but it will not work on you phone.