You can do the whole save SHSH and start TSS server to restore that way if you want. It is easier just to open and close it though as I said that sets your hosts to cydia so that you will be able to restore to the custom firmware.
I have download 4.0.1 fw so that I can unlock my iphone. However, when I opened the snowbreeze and browse to 4.0.1, it stated that not a valid ipsw. Do I have download 4.1 fw? if I upgrade from 3.0.1 with the baseband 04.26.08 to 4.1, do my phone loose its baseband and can't be unlock? Thank you for your time and happy new year
If you are going the snowbreeze route then 4.1 is the firmware you will go to. Snowbreeze will make a custom firmware with no baseband update in it so that you can still unlock.