I had recently tried to use the force update method but had no success with it so i tried the seven eighter tool developed by windowsphonehacker
It works like a charm all you have to do is click a button and there you go
during the process your phone might restart a couple of times as updates are being applied so don't worry and have patience !!!!
thank you to these guys i could update my htc radar in india to 7.8
SevenEighter: Want Windows Phone 7.8 now? Try this easy tool (Update: Now supports 8862!) - Windows Phone Hacker
It works like a charm all you have to do is click a button and there you go
during the process your phone might restart a couple of times as updates are being applied so don't worry and have patience !!!!
thank you to these guys i could update my htc radar in india to 7.8
SevenEighter: Want Windows Phone 7.8 now? Try this easy tool (Update: Now supports 8862!) - Windows Phone Hacker