Today I updated my HTC Desire to Android 2.2. The update was successful but I noticed one problem; my mobile internet didn’t connect any more. I found out that I had to add (or delete and add new) APN carrier settings in: Settings → Wireless & networks → Mobile networks → Access Point Names.
For a list of settings of Dutch and Belgium mobile network operators see this page.

Hi Marthijn,
Friday I updated my wildfire to 2.2 and experienced the same problem: No mobile internet connection anymore. With other less restrictive search criteria I luckily found your site and also the solution to solve this issue. In the previous days other sites I found recommended clear storage, reset phone bladibla solutions….
In my case I only needed to add the username and password to the existing APN.
Thanks and a happy newyear!
Dennis Nieland
1) Pull your battery
2) Dial *2 talk or make a short active call, then hangup (this grabs a tower and speeds up the next step)
3) menu>settings> about phone/system updates> update profile.
Once complete test Google
That outa do it.
You can also always try a data Restore (##3282#) but you’ll need the MLS (Master Subsidy Lock Code) from a sprint rep or from Sprint Chat