Now this is easy once you get the hang of it you will need 4 things

1: A USB Data Cable: - (mobilefun.co.uk - do very good data cables)
2: GX15 Upgrading Tool - (can be found Here)
3: Flash Files (Now i have one stored on my website which is NON Vodafone More can be found Here)
4: USB Drivers - (Make sure there are install Can be found Here)

STEP1:
Install all drivers for the USB cable and then install the GX15 Upgrading Tool

STEP2: Download the flash files you want either the non vodafone one or the other on that other site.

STEP3: Now make sure your phone has a full battery and also no sim card inside the phone.

STEP4: Now load up the GX15 Upgrading Tool and select the flash file you want to use into the program like shown in the picture below: Click on the Image for a bigger picture.



STEP5: Now once you have that all that sorted click on "START LOADING FLASH"

STEP6: Now your phone will flash that file you have selected should be done in about 5-10mins don't touch anything while you are flashing your phone after its finished take out the USB cable put a sim card in and check out your new flash file.