This is the iPhone OS system the iPhone runs. Latest Apple download links can be found here.
Comparison of firmware versions
| Version | Build | Baseband | IPSW Download URL | SHA1 Hash | Comments | Can be jailbroken? | Can be unlocked OTB? | File Size | 
| 1.0 | Alpine 1A420 | 03.06.01_G | iphoneproto.zip | 6e798e906c6590a7521ef89b731569be6d05b3aa | Prototype; macrumors | Yes | No | 109,813,128 | 
| 1.0.0 | Heavenly 1A543a | 03.12.06_G | iPhone1,1_1.0_1A543a_Restore.ipsw | fb8bb3ee2e9a997affbb97868599f2995c78209c | Initial US shipment. | Yes | Yes | 95,604,348 | 
| 1.0.1 | Heavenly 1C25 | 03.12.06_G | iPhone1,1_1.0.1_1C25_Restore.ipsw | a00b85a7a55d62a94be5fbf5effbc42fd63f3097 |  | Yes | Yes | 95,627,958 | 
| 1.0.2 | Heavenly 1C28 | 03.14.08_G | iPhone1,1_1.0.2_1C28_Restore.ipsw | 7f5c0ff1f84a0202b75a55c3fcb362e415334d1e |  | Yes | Yes | 95,627,324 | 
| 1.1.1 | Snowbird 3A109a | 04.01.13_G | iPhone1,1_1.1.1_3A109a_Restore.ipsw | d441dd1c71ce18f25d8fc4faa71c1e6eaa02d02c |  | Yes | Yes | 159,668,150 | 
| 1.1.2 | Oktoberfest 3B48b | 04.02.13_G | iPhone1,1_1.1.2_3B48b_Restore.ipsw | 797c02e7d660940e8d9a16cc7229ccf3f67dd8b1 | Initial Euro shipment. | Yes | Yes | 167,927,501 | 
| 1.1.3 | Little Bear 4A93 | 04.03.13_G | iPhone1,1_1.1.3_4A93_Restore.ipsw | b3dec7580bd00dc4faf28449d9618ef40aeacc96 |  | Yes | Yes | 169,950,551 | 
| 1.1.4 | Little Bear 4A102 | 04.04.05_G | iPhone1,1_1.1.4_4A102_Restore.ipsw | 000811bac096011b50ebf6ec1ec2285b62fda4cb |  | Yes | Yes | 169,946,442 | 
| 2.0 | Big Bear 5A347 | 04.05.04_G | iPhone1,1_2.0_5A347_Restore.ipsw | 9c510a3cfce789fa5f92a8f763c231bac82ff6d4 |  | Yes | Yes | 228,768,637 | 
| 2.0.1 | Big Bear 5B108 | 04.05.04_G | iPhone1,1_2.0.1_5B108_Restore.ipsw | 61de6a2bd6ceddc9ecabad1671b91a59b3824bc4 |  | Yes | Yes | 254,048,068 | 
| 2.0.2 | Big Bear 5C1 | 04.05.04_G | iPhone1,1_2.0.2_5C1_Restore.ipsw | b84b57bea919bdc720287ec908c1378e7d7b5e1b |  | Yes | Yes | 253,589,000 | 
| 2.1 | Sugar Bowl 5F136 | 04.05.04_G | iPhone1,1_2.1_5F136_Restore.ipsw | 353b7745767b85932e14e262e69463620939bdf7 |  | Yes | Yes | 242,171,241 | 
| 2.2 | Timberline 5G77 | 04.05.04_G | iPhone1,1_2.2_5G77_Restore.ipsw | cbfc6ff886ce89868a55547b9fb980dbf92e6418 |  | Yes | Yes | 257,576,980 | 
| 2.2.1 | SUTimberline 5H11 | 04.05.04_G | iPhone1,1_2.2.1_5H11_Restore.ipsw | 43b95ebe1e51f8d30eae916053396595c08440d3 |  | Yes | Yes | 257,593,705 | 
| 3.0 | Kirkwood 7A341 | 04.05.04_G | iPhone1,1_3.0_7A341_Restore.ipsw | 2afd3f8ede17390737f508473ed205506a0bd23f |  | Yes | Yes | 240,394,111 | 
| 3.0.1 | Kirkwood 7A400 | 04.05.04_G | iPhone1,1_3.0.1_7A400_Restore.ipsw | 34c391fbbc7b31b159372766de39ce5c9cc26ebb |  | Yes | Yes | 240,439,502 | 
| 3.1 | Northstar 7C144 | 04.05.04_G | iPhone1,1_3.1_7C144_Restore.ipsw | b7b5f436f81c6f855410e8b44a3d432ccaacd6fc |  | Yes | Yes | 252,536,460 | 
| 3.1.2 | Northstar 7D11 | 04.05.04_G | iPhone1,1_3.1.2_7D11_Restore.ipsw | e4a1171542dbbd3093516d9c02047b9f7e143050 |  | Yes | Yes | 252,515,888 | 
| Version | Build | Baseband | IPSW Download URL | SHA1 Hash | Comments | Can be jailbroken? | Can be unlocked OTB? | File Size | 
| 2.0 | Big Bear 5A345 | 01.45.00 | No download available |  | Initial iPhone 3G shipment. | Yes | Yes (Upgrade to 04.26.08) |  | 
| 2.0 | Big Bear 5A347 | 01.45.00 | iPhone1,2_2.0_5A347_Restore.ipsw | af9506ca0034e462674f9f59c5406f159eaf9fc1 |  | Yes | Yes (Upgrade to 04.26.08) | 235,957,125 | 
| 2.0.1 | Big Bear 5B108 | 01.48.02 | iPhone1,2_2.0.1_5B108_Restore.ipsw | e81c7ac7e334a3e9d81b3b47894bfaa1ec495482 |  | Yes | Yes (Upgrade to 04.26.08) | 261,224,227 | 
| 2.0.2 | Big Bear 5C1 | 02.08.01 | iPhone1,2_2.0.2_5C1_Restore.ipsw | bef7fef954293046420fbcf947379839178a195b |  | Yes | Yes (Upgrade to 04.26.08) | 260,761,030 | 
| 2.1 | Sugar Bowl 5F136 | 02.11.07 | iPhone1,2_2.1_5F136_Restore.ipsw | c6957dcbf2a95ccfd6dce374a727b1b7700a9043 |  | Yes | Yes (Upgrade to 04.26.08) | 249,341,655 | 
| 2.2 | Timberline 5G77 | 02.28.00 | iPhone1,2_2.2_5G77_Restore.ipsw | f67f8b2b842428bf89456cda0c2d5cf954d111a4 |  | Yes | Yes (Upgrade to 04.26.08) | 258,342,348 | 
| 2.2.1 | SUTimberline 5H11 | 02.30.03 | iPhone1,2_2.2.1_5H11_Restore.ipsw | e0098e6fab5c90b59e067e03ae3ccd4a7cd0f39c |  | Yes | Yes (Upgrade to 04.26.08) | 258,359,073 | 
| 3.0 | Kirkwood 7A341 | 04.26.08 | iPhone1,2_3.0_7A341_Restore.ipsw | 94f1fb43de12bff0f168ce690b7e794cc6220ae3 |  | Yes | Yes (with ultrasn0w) | 241,229,233 | 
| 3.0.1 | Kirkwood 7A400 | 04.26.08 | iPhone1,2_3.0.1_7A400_Restore.ipsw | a148ff39fa4dea499e7a9dd007b63e90c4f56666 |  | Yes | Yes | 241,274,617 | 
| 3.1 | Northstar 7C144 | 05.11.07 | iPhone1,2_3.1_7C144_Restore.ipsw | 9b3b3c148170b012012278efda9ff5c38282d559 |  | Yes | No (Though you can stay at 04.26.08) | 253,361,339 | 
| 3.1.2 | Northstar 7D11 | 05.11.07 | iPhone1,2_3.1.2_7D11_Restore.ipsw | b1a6ab2771bb5da372ba75a8fa3e1d72b71359d0 |  | Yes | No | 253,340,786 | 
| Version | Build | Baseband | IPSW Download URL | SHA1 Hash | Comments | Can be jailbroken? | Can be unlocked OTB? | File Size | 
| 3.0 | Kirkwood 7A341 | 04.26.08 | iPhone2,1_3.0_7A341_Restore.ipsw | d8534408c8679c830fd0c4e36ef9762c11ef73df | Initial shipment. | Yes | Yes (with ultrasn0w or purplesn0w) | 312,292,933 | 
| 3.0.1 | Kirkwood 7A400 | 04.26.08 | iPhone2,1_3.0.1_7A400_Restore.ipsw | 30006575af931e3da0521febace005152cdb8853 |  | Yes | Yes | 312,330,244 | 
| 3.1 | Northstar 7C144 | 05.11.07 | iPhone2,1_3.1_7C144_Restore.ipsw | 527c74f87588afa1d69c1e2c08eedc88f113013a | Installed on phones produced week 37. | Yes | No (Though you can stay at 04.26.08) | 321,011,474 | 
| 3.1.2 | Northstar 7D11 | 05.11.07 | iPhone2,1_3.1.2_7D11_Restore.ipsw | 6998bb7d9e869b2d89a08853312f9457d070fb1f |  | Yes (with blackra1n) | No (Though you can stay at 04.26.08) | 321,015,700 | 
| Version | Build | IPSW Download URL | SHA1 Hash | Comments | Can be jailbroken? | File Size | 
| 1.1.0 | Snowbird 3A100a | No download available |  | Initial shipment. | Yes |  | 
| 1.1.0 | Snowbird 3A101a | iPod1,1_1.1_3A101a_Restore.ipsw | 9b0d83c7f8b4328174a3f31e0e93f60e591ae143 |  | Yes | 157,890,186 | 
| 1.1.1 | Snowbird 3A110a | iPod1,1_1.1.1_3A110a_Restore.ipsw | 84bbc6ea8bf29745195bc9926c1874f7c2a36f32 |  | Yes | 157,906,686 | 
| 1.1.2 | Oktoberfest 3B48b | iPod1,1_1.1.2_3B48b_Restore.ipsw | 108d8ffe9ea75e61cd5e57170ad388b7fa00d923 |  | Yes | 165,567,897 | 
| 1.1.3 | Little Bear 4A93 | iPod1,1_1.1.3_4A93_Restore.ipsw | 8dca23eec69d5ae58fbf3d4a23276e46cbb2e3c6 |  | Yes | 173,511,411 | 
| 1.1.4 | Little Bear 4A102 | iPod1,1_1.1.4_4A102_Restore.ipsw | c148d1eb1c979bb6434175411d4a372103a4fdd2 |  | Yes | 173,519,589 | 
| 1.1.5 | Little Bear 4B1 | iPod1,1_1.1.5_4B1_Restore.ipsw | 1b818911316e4248ee01d3ec67f9d39afc3db240 |  | Yes | 173,519,637 | 
| 2.0 | Big Bear 5A347 | Download Link Prohibited | ae82798e85f9953b0f4798bad36187cb020c9d22 | 2.0+ is a paid upgrade series | Yes | 233,409,573 | 
| 2.0.1 | Big Bear 5B108 | Download Link Prohibited | a81b6e7af4b85ef436d047f9da57c0f694d8964a |  | Yes | 258,660,321 | 
| 2.0.2 | Big Bear 5C1 | Download Link Prohibited | c8b6f9fefa3f3777c56285dfe4c735b1e08a81a2 |  | Yes | 258,201,218 | 
| 2.1 | Sugar Bowl 5F137 | Download Link Prohibited | fc7f6d0972927df502ffca47438ca75dcccffaf3 |  | Yes | 251,155,156 | 
| 2.2 | Timberline 5G77 | Download Link Prohibited | 081a7de363230fb38d0ce092cbbe42f2a50c8a5f |  | Yes | 260,186,851 | 
| 2.2.1 | SUTimberline 5H11 | Download Link Prohibited | fc69be9e421bc0630567184506ab771f6b7ef68b |  | Yes | 260,166,688 | 
| 3.0 | Kirkwood 7A341 | Download Link Prohibited | dff2bd14931225908a360fb8e60a336f17d2dd6d | 3.0+ is a paid upgrade series | Yes | 242,458,552 | 
| 3.1.1 | Northstar 7C145 | Download Link Prohibited | c6270780c166db4c9f4f0a7fa945754a1f9fe7e8 |  | Yes | 249,755,862 | 
| 3.1.2 | Northstar 7D11 | Download Link Prohibited | 7367dd9ba58a3b9777307368a0128e696fdfc9a6 |  | Yes | 249,780,497 | 
| Version | Build | IPSW Download URL | SHA1 Hash | Comments | Can be jailbroken? | File Size | 
| 2.1.1 | Sugar Bowl 5F138 | iPod2,1_2.1.1_5F138_Restore.ipsw | c3c700be49ad227d1152188e7c1e46b8958fd1e4 | Initial shipment. | Yes | 282,083,944 | 
| 2.2 | Timberline 5G77a | iPod2,1_2.2_5G77a_Restore.ipsw | 34a0a489605f34d6cc6c9954edcaaf9a050deedc |  | Yes | 291,123,491 | 
| 2.2.1 | SUTimberline 5H11a | iPod2,1_2.2.1_5H11a_Restore.ipsw | 9af5625ea34acdd8abeb6fce71a72651d0c815d5 |  | Yes | 291,140,244 | 
| 3.0 | Kirkwood 7A341 | Download Link Prohibited | 0f7fc76d9b9aa826b5ab14be9821a315d3d9dc42 | 3.0+ is a paid upgrade series | Yes | 270,315,364 | 
| 3.1.1 | Northstar 7C145 | Download Link Prohibited | e0d8800a4fc7cc5be6976ddbceb43c2d2a7120d7 |  | Yes, if upgraded from 3.0 | 277,753,989 | 
| 3.1.2 | Northstar 7D11 | Download Link Prohibited | e7c83d4a5baec0e81816ae1cd1caf9a4dc38ebf0 |  | Yes | 277,794,671 | 
| Version | Build | IPSW Download URL | SHA1 Hash | Comments | Can be jailbroken? | File Size | 
| 3.1.1 | Northstar 7C145 | iPod3,1_3.1.1_7C145_Restore.ipsw | a3eddbe2cf77858bae7087dc8b2035f0d3097e57 | Initial shipment. | Yes, but only tethered one | 311,702,789 | 
| 3.1.1 | Northstar 7C146 | iPod3,1_3.1.1_7C146_Restore.ipsw | f66a7286b261137f25ddbbd84047f9a7ea181904 |  | Yes, but not yet released | 311,690,768 | 
| 3.1.2 | Northstar 7D11 | iPod3,1_3.1.2_7D11_Restore.ipsw | 02dcee28d788d594a2939ab564f4f183af6ccdf2 |  | Yes, but only tethered one | 311,740,034 | 
See also
Resources