I had the same problem with my iphone 3g 16g and I was able to fix it. You may do the same before mo mag-restore. Ang nakakuyaw sa restore kung jailbroken imo phone kay basinn ma SWOD na hinoon.
SWOD stands for spinning wheel of death, and this happens when the phone restarts after restoring and will not boot back on.
Try these steps:
1. check under settings >>> wifi - kung greyed out ang wifi, guba ang wifi chip sa iphone or naay issue ang connection sa chip ug logic board (fix: an iphone tech should be consulted)
2. if you are on a home network nya maka-connect ang uban wireless devices except sa iphone, wireless settings sa router ang issue (fix: i-change ang wireless channel ug encryption sa router)
3. go to settings >>> general >>> reset >>> reset network settings
4. go to settings >>> turn on airplane mode >>> with the airplane mode on, go to wifi and try to detect a wifi network.. kung walay ma-detect kay balik sa settings nya i-off ang airplane mode then balik nasad sa wifi
5. try to remember the most recent change that you did to your iphone.. kung naa moy gi-install nga app nya after ana nagkaproblema na ang wifi, uninstall it
and the last step which i think solved my issue
6. connect the iphone to your PC or MAC and open itunes... i-back up ang imo phone sa itunes...
disconnect the cable >>> reset network settings >>> turn on airplane mode >>> go to wifi >>> turn off aiplane mode >>> go back to wifi (and viola! my iphone is now detecting my wifi network)
If any of the steps fixes your issue, kindly let us know which step, para benefit pud sa uban nga naay pareho ug problema sa atoa.