Where can I download 4.x firmware files for the iPhone 3GS?

Where can I download 4.x firmware files for the iPhone 3GS?

Apple's iPhone 3GS shipped with the iPhone 3.0.0 operating system and runs firmware version 4.x with some limitations. On your computer, right-click the link below to download the official firmware restore file.

iPhone 3GS firmware version 4.0.0 can be found here: iPhone2,1_4.0_8A293_Restore.ipsw
iPhone 3GS 4.0.1: iPhone2,1_4.0.1_8A306_Restore.ipsw
iPhone 3GS 4.0.2: iPhone2,1_4.0.2_8A400_Restore.ipsw
iPhone 3GS 4.1.0: iPhone2,1_4.1_8B117_Restore.ipsw
iPhone 3GS 4.2.1: iPhone2,1_4.2.1_8C148a_Restore.ipsw
iPhone 3GS 4.3.0: iPhone2,1_4.3_8F190_Restore.ipsw
iPhone 3GS 4.3.1: iPhone2,1_4.3.1_8G4_Restore.ipsw
iPhone 3GS 4.3.2: iPhone2,1_4.3.2_8H7_Restore.ipsw
iPhone 3GS 4.3.3: iPhone2,1_4.3.3_8J2_Restore.ipsw
iPhone 3GS 4.3.4: iPhone2,1_4.3.4_8K2_Restore.ipsw
iPhone 3GS 4.3.5: iPhone2,1_4.3.5_8L1_Restore.ipsw