Force iPhone 4 to always use 3G

Recently I was working using internet tethering on my iPhone 4 in an area of patchy reception, but if I put my phone in a certain position I knew it could use the 3G network. Unfortunately the phone isn’t very good at jumping up to 3G and will instead use Edge or a slower band. Here is how to force your iPhone to use 3G if know there is a 3G signal:

Things you will need:

• To be able to ssh into your phone (I did this by jailbreaking it – do so at your own risk)
• A text editor on the phone (I installed nano from cydia)


ssh root@iph4ne.local
cd /var/wireless/Library/Preferences/
nano csidata

then change this line:

GsmRegistrationModel::fRatSelection=0×1

to

GsmRegistrationModel::fRatSelection=0×2

Save the file, then finally:

reboot


Which will force your iPhone to use 3G. WARNING: only do this if you know you will have access to a 3G network otherwise you will loose your net connection.