Try going through this process to download the update manually.
Note 1*- This is for stock non-rooted users ONLY.
1. Download the update.zip file from here. (DIRECT FROM GOOGLE.)
2. Drop the file on the root of your SD card. (Meaning, don’t put it in any folder.)
*MAKE SURE IT’S NAMED UPDATE.ZIP!
3. Turn your phone off.
4. Press and hold the Volume Down and Power at the same time to boot into HBOOT.
5. When the white HBOOT screen appears, use the volume button to move down to “RECOVERY.”
6. Press the Power button to select “RECOVERY.”
7. When the triangle and exclamation appears, hold the Volume Up and Power button at the same time.
8. Using the volume button, scroll down to “apply sdcard:update.zip” and select it.
9. Your phone will now update!
10. It could take some time, so be patient. When it reboots, you are on official 2.2.
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