you can try doing a full restall but using redsn0w then ultrasnow, only prob you'll lose your MMS like the rest of us. The carrier profile works on unlockit.co.nz. I'm guessing you have put in your APN details into the cell data settings if you have it, mine all disappeared.

settings->general--->network----> cell data settings then google your provider and iphone settings apn....

u sound like you know what your doing so I guess you have?

yep everyone on a 3G jailbroken see unlockit.co.nz if your having a problem with ure internet not working...no apn settings too they have disappeared for alot of us:(

don't bother go to unlockit.co.nz and find your provider send yourself the profile and your back on the net via phone, just connect using wifi. open the email sent and your back on line, no fix for the mms,

hi mate,

had the same issue my mms still does not work. I spent all night looking for a fix, no point doing a full install again, connect to the internet via wifi, open safari and type "unlockit.co.nz" once you go to the page find your o2 uk settings and email your self the profile, check your email on your phone and unlockit will send you an email with a file, open the file and hey presto. This has worked for everyone so far, there seems to be a problem with the jailbreak locking the cell data settings and not allowing the option. No fix for the MMS so far, hope the IDEV guys can work that out, this problem only affects 3G jailbroken phones with a sim not originally from the provider.

That should work, don't bother doing clean installs etc, i did that all night and found the fix, thanks Unlockit.co.nz there the greatest man