Beta OTA Updates/iPhone/5.1

iPhone 3GS

Version	Build	Prerequisite Version	Prerequisite Build	Release Date	OTA Download URL	File Size
5.1 beta 3	9B5141a	5.0.1	9A405	9 January 2012 (2012-01-09)	6741d7662fe6146bcdbec441762470b08ed0c8b1.zip	110,456,279
5.1 beta 3	9B5141a	5.1 beta 2	9B5127c	9 January 2012 (2012-01-09)	ffd65cefb4f892725a2592960f953a31944872e2.zip	64,373,565
5.1 beta 4	9B155^[1]	5.0.1	9A405	23 January 2012 (2012-01-23)	14d2d3b74ffc2c926e24131c6f16ec545ee37792.zip	110,756,001
5.1 beta 4	9B155^[1]	5.1 beta 3	9B5141a	23 January 2012 (2012-01-23)	1730afb4780176c39c84c9aa0a115f417008403a.zip	46,407,494

iPhone 4

iPhone3,1

Version	Build	Prerequisite Version	Prerequisite Build	Release Date	OTA Download URL	File Size
5.1 beta 3	9B5141a	5.0.1	9A405	9 January 2012 (2012-01-09)	14f8af06cff79045e3682287c8f51d99ac9eb4fd.zip	185,432,127
5.1 beta 3	9B5141a	5.1 beta 2	9B5127c	9 January 2012 (2012-01-09)	f7b405cca1af5de58a49c63772e59a8feb17a877.zip	71,922,963
5.1 beta 4	9B155^[1]	5.0.1	9A405	23 January 2012 (2012-01-23)	db85e197c6336866a2b22b07bb13716606060bb8.zip	185,832,575
5.1 beta 4	9B155^[1]	5.1 beta 3	9B5141a	23 January 2012 (2012-01-23)	6ca371c561317106a2e88ff31e796bc725f156ea.zip	52,820,262

iPhone3,3

Version	Build	Prerequisite Version	Prerequisite Build	Release Date	OTA Download URL	File Size
5.1 beta 3	9B5141a	5.0.1	9A405	9 January 2012 (2012-01-09)	962bb18b9ceb4f651fd1fd63b1dcd4fbb5171fd0.zip	195,143,783
5.1 beta 3	9B5141a	5.1 beta 2	9B5127c	9 January 2012 (2012-01-09)	d504ee2e5a295880ef9ddef8f2e95749463c5c2d.zip	81,120,562
5.1 beta 4	9B155^[1]	5.0.1	9A405	23 January 2012 (2012-01-23)	76408733a9812ff779e8a5db854a7ea2385101f2.zip	195,396,452
5.1 beta 4	9B155^[1]	5.1 beta 3	9B5141a	23 January 2012 (2012-01-23)	b5f9ecc79d22e6af519ed00506bffc04966daee5.zip	62,351,550

iPhone 4S

Version	Build	Prerequisite Version	Prerequisite Build	Release Date	OTA Download URL	File Size
5.1 beta 3	9B5141a	5.0.1	9A405	10 January 2012 (2012-01-10)	21b1b074d027e09b80905144afc9e0ab7cb15636.zip	197,887,316
5.1 beta 3	9B5141a	5.1 beta 2	9B5127c	10 January 2012 (2012-01-10)	5e15af51bc7ee8c741d7b25dd1ae7653dcb1efb3.zip	79,997,780
5.1 beta 4	9B155^[1]	5.0.1	9A405	23 January 2012 (2012-01-23)	dd4830bae0b342df01962d4dca1889b90854f82b.zip	198,204,236
5.1 beta 4	9B155^[1]	5.1 beta 3	9B5141a	23 January 2012 (2012-01-23)	44a83b77f8dec754a4e722a1fab97ced1288f7b6.zip	60,775,251

^ ^a ^b ^c ^d Apple inflated the build number in its mesu.apple.com listing, presumably to make the device recognize the update. (e.g. 12F61 was listed as 12F5061.) The listings on this page use the build number displayed on the device.