This iPhone isn't eligible for the requested build iOS 4.3.3

When you are trying to upgrade the iPhone, iPod touch, or iPad firmware to iOS 4.3.3, iTunes must be able to connect to Apple server during verification process while restoring the firmware. If your computer failed to connect to Apple server, restore process will be stopped and stuck on “device isn’t eligible for the requested build” error message.

How-to fix this iPhone isn’t eligible for the requested build iOS 4.3.3 error?

1. Open Notepad using Administrator’s rights or Administrator’s account on Windows. Start → All Programs → Accessories → right click Notepad → Run as Administrator.
2. Click File → Open → browse to C:Windowssystem32driversetc and select hosts file.
   
   Use text editor and edit /etc/hosts file on Mac (run as root or use sudo)

   Find this line:
   74.208.105.171 gs.apple.com
   Or
   74.208.10.249 gs.apple.com

   Then

3. Add # sign to the front of it.

   Or, you can simply delete that line.

   Both are IP addresses of Cydia Servers where your SHSH Blobs information will be saved. Adding # sign into that line on your hosts file means that you are making that line as a comment. Or simply delete it from the entries will make your Windows contacting Apple server normally during restore process.

   

4. Save the changes by clicking File → Save or pressing Ctrl + S.

   To verify that you did it correctly, type ping gs.apple.com on command prompt on Windows Accessories (Spotlight → Terminal → ping on Mac) and it must be resolved to 17.112.176.11.

   Example:

   C:>ping gs.apple.com

   Pinging gs.apple.com [17.112.176.11] with 32 bytes of data:
   Reply from 17.112.176.11: bytes=32 time=427ms TTL=49
   Reply from 17.112.176.11: bytes=32 time=429ms TTL=49
   Reply from 17.112.176.11: bytes=32 time=468ms TTL=49
   Reply from 17.112.176.11: bytes=32 time=447ms TTL=49

   Ping statistics for 17.112.176.11:
   Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
   Approximate round trip times in milli-seconds:
   Minimum = 427ms, Maximum = 468ms, Average = 442ms

   C:>

   If you’re getting anything else then it is not good.

   Now, the restore should run smoothly without error “This iPhone (iPad or iPod) isn’t eligible for the requested build” when you are upgrading to iOS 4.3.3