1. you download the iPad ipsw
2. download the pwnagetool 4.1.3 unlock edition
3. open pwnage tool, klick on your device, and then choose the iOS 4.1 firmware bundle
4. then after going to the next page, there wil pop up a windowd which asks you if you want to use the ipad baseband. click yes
5. now the custom ipsw is being created.
6. open up itunes and alt + click on restore button , and choose the custom created ipsw.
7. now you can download ultrasnow trough cydia to unlock