1. Close Diablo 3.

2. Copy the file "hosts" to desktop. (*1)

3. Right click desktop's "hosts" file > Open > choose "Notepad" > OK

4. Copy following words and paste below.

1. 1. ####################################
2. us.patch.battle.net 12.129.206.133

12.129.206.133 enUS.patch.battle.net
12.129.206.133 esMX.patch.battle.net
12.129.206.133 ptBR.patch.battle.net

1. eu.patch.battle.net 213.248.127.133

12.129.206.133 enGB.patch.battle.net
12.129.206.133 deDE.patch.battle.net
12.129.206.133 frFR.patch.battle.net
12.129.206.133 itIT.patch.battle.net
12.129.206.133 plPL.patch.battle.net
12.129.206.133 esES.patch.battle.net

1. kr.patch.battle.net 121.254.200.133

12.129.206.133 zhTW.patch.battle.net
12.129.206.133 koKR.patch.battle.net

1. sg.patch.battle.net 202.9.66.78

12.129.206.133 enSG.patch.battle.net

1. 1. ####################################

5. Then File > Save file.

6. Copy desktop's "hosts" file back, and Overwrite.

7. Restart Diablo 3, and it will connect to enUS update Server.

P.S.
1. The "hosts" file is in "C:\Windows\System32\drivers\etc\hosts"