try a smaller flash drive, 16GB ones reported as too large for the nav system in some posts
8 gb max for the version updates
tweaks only need 1gb or less really, it's only a few lines of code
use the v55.753_Apply_Tweaks_USB_Speed_Disclaimer_WiFi ones in the Index topic, coded for auto install or go back
extract these files to a blank fat32 usb, plug it in, then turn on the car, after around 20 seconds, a window should appear saying the tweaks were applied, then after another few seconds a second window will say the data has been collected or something. Restart the CMU by holding Back+Nav+Mute for 10 seconds and WiFi should be enabled.
no offense - but it's always better to go directly to the source - read some of the background so you understand the benefit & risks of what you're about to do
the infotainment index topic has all the links
http://mazda3revolution.com/forums/...ronics/104730-index-infotainment-project.html
scroll down to the tweaks section, there's a link mid paragraph about instructions
http://mazda3revolution.com/forums/1337690-post154.html