Warning - if you don't fully understand the dangers of flashing new firmware into a device (especially unofficial firmware) then DO NOT PROCEED - you could turn your Mifi into a useless plastic pebble!!!
This process requires a Windows XP PC and the Mifi USB cable
Step 2) Switch off your Mifi and remove the SIM card (requires you to remove the back cover, remove the battery, and then replace battery and back cover).
Step 3) Put the Mifi into firmware flashing mode by holding down the power and dial-up buttons together for about 5 seconds until they both illuminate.
Step 4) Connect the Mifi to the Windows XP PC using the USB cable. If the Three Mifi manager software starts up then close it before flashing the firmware.
Step 5) Run the firmware exe file and proceed through the wizard. Flashing takes about 10 minutes.
Step 6) When finished, disconnect and power down the Mifi, replace the SIM card, and power it up.
Step 7) Log in to the admin interface on 192.168.1.1 using username and password "admin"