need help updating ACHH3

[Guest JAK987]

hi Im new to phone upgrading and need help please?I recently bought a vodafone branded samsung omnia i900 but I use orange network so I got it unlocked.the firmware is ACHH3 and I want t update it to ACHJ2 but im concerned this will either brick my phone? or cause it t revert back to vodafone only? what should I do? help appreciated :D thanks

[Guest JAK987]

*bump*

anybody? i need help ive searched google 3 days straight now :D