OTA firmwares cannot be restored to. IPSW Downloads collects them for potential future use. They might also be useful if you're doing research.
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.4 GiB | d886abe5b225813b50bfdb3cfada663e72a44c8e.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.4 GiB | 0842dc23926454fac4a579454e25aa30406780fd.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.4 GiB | d626f9ee34a8837fb9ab93efe3e8f57f6a861ed2.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.4 GiB | e0f696756e699b01fe18b3e039895d32336c26d6.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.4 GiB | df3e6b2da5a5622d39e94d5dd0884a7ddda7fb89.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.1 (16R591) | October 30, 2018 | 1.4 GiB | 27fc6f677188316dc9e9803f32eb8324d544166f.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.1 (16R591) | October 30, 2018 | 1.4 GiB | 166ee2e9b239d84d595f7bc10604329b8d6c0de5.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.4 GiB | e20d9f04b046416303a3e75b76edb4f05dae530e.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.4 GiB | 95b65d8ea257fc2d3446237d03ccd96221e78b7f.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.4 GiB | 36915bbe9c39ab0afc151d932e8e47435b7a2835.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.4 GiB | 2f2522d0df12c759c04701e3f0350d46bc3596b6.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.4 GiB | 6b0015532ef267e9c93063c9ffea07034c71aa3c.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | bd05a9a5827b9afec1a633d40e659c70062548fd.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | fbc5252629bf2d0e93d89fc0bddd9490f2ccbc26.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | 7ad704ff12aac40d522b39e0cd41d98c62332bc0.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 2ea14543eaa2bb0473ab1bf21f5e76ef6e362a45.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | dff9e7e5a5d53f7c398ebebe6280235b58bad482.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | 1d98882361caa54b4186d044c6b9f289b93d45df.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 979f0dc4512b9054559960653cfbc347aeab9bd9.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | 98f28bcf15c7b0d98d1a156b203c075ea0f85c9e.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | 44657e056d4bfdc5b69fa859e6b8991715a627b5.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | 3547c96155b115374dca8dddcf8faa101f343cbb.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | 93d1f8f6c15d8e9d50d5836218497dcb1b96d6ca.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | e98c88e2202495103cfee7652e3e8773fccc78cc.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | af76a4d2da9435109cabb4d3bed8840575cb3cbe.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | a4dc5ec585bb7a736e7ddbbb76fd2d372fcb1fe7.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | c14f9608bc4955d2e8cb83cd69c060c7700270a3.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | a1f83fc063c0c9bbc8a7535ae0251e95bec69f56.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | 5d18c734e676e161d59d56085f97887cd6256a0e.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | 0b81582043029bc0af47cd9439eeed18cb849cc2.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | 7b1778eabea8bf655f93f65f00bd4f3d3d062f2e.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | d24dc238f87a11b8cc4016cd382043c5525b49c9.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | 7247c20578cb894e19867bedf60f7a690811f449.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 31c71952777a34ee48fb752756c7aa3a1c42a786.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | ecc63c55431c47ca3b1c8eb20e4cc3e6c58cbc1f.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | 37e2dfec6df0fd5639d8dc0417577c87b7a8d3c2.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | 1c02ee71482a6350802a5e2ff2843a53f0adfb0a.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | 809001522e8eb705f2268c1b8a8a0b627d754ecf.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 7b489d714c834b42ea81ea67e2d12b424a83657c.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | c11f0220e7c6ce6760fd34feaed9bd2ac3ccf932.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | 7fa3a7cdf6622818fa6b10354253a340f5a34dc2.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | d4f513438a62cd77bbc21f26d2ac872502dba6f4.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | aded76c7dd446e0111e4a3c2f5f88ecab585ccf0.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | f4b395d4b9d70049916dc2cfda2bc9ebbbe48209.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | e5ea1837d5071984b892faeaf9b57609698f9082.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | cece9c8707cebfc49b732e8b0f00224a649cd247.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | cf000eee7ba0d4cce0362a086958718e7d6dddee.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | a64751cf07d1ace198fc31f6ac0d68b1f3d573af.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | 6c7cbaeb92bd70203223cb2889a81bad8355b9b0.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | 702cdf7d3a9c54c7f860f405c584f1cc96a197a4.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 88dfc562f19be25e9c023fa9cfa458e865cb7da9.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | d31eb12fda20fe1c95aaf20ee8379b700c7c6c89.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | 6e7da5b4843a701114d4fdae897c201dd1e94c9d.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | dd0fa116f8011c7ed6122962ceeae2df13441a9c.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | f937ef36250602bd8a426dca75287b28367ca39c.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | f123c7b3b566596889f43d6bf11c8e7ec4331199.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | 691d05585e96e39538d87171315cf48de43a5911.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | 8a0ac55d09c74c43cb924ba5b5cde36b580aef4a.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.2 GiB | 9e5e0bb95b80d98e9a6ccccf87d133d17f29c59c.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | 1ddaf681a6c8b2bf5b9c396f004553b1efd1daef.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | 54bdc9558da13658f97e239417e71a89897ece52.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | aee69ec80f5a37400c91054bf48cd24d272d2e9f.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 6d28f3847afdea00868c2c0be58ebd5bc656b631.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | 09c26ff3051bb08e2b426b337e726134bfb38c7c.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | bf54111073cb384c3bf42bf0450b5cec7b54cae4.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | 0c2615b20ff05423f932ff3c029d9e2eb9f99ce5.zip |
| ✗ | Apple Watch Series 2 (38mm) | watchOS 5.1 (16R591) | October 30, 2018 | 1.3 GiB | 2d9b19d6ff578f0d0d869c8abb7588a59aa445b8.zip |
| ✗ | Apple Watch Series 2 (38mm) | watchOS 5.1 (16R5559d) | September 18, 2018 | 1.3 GiB | 0267724b87bb9fbd1e4859da62bfc62cd8eb510f.zip |
| ✗ | Apple Watch Series 2 (38mm) | watchOS 5.1 (16R5568d) | October 2, 2018 | 1.3 GiB | 79cfa2dd75d3dd1c69ac33ca54d6c5026a459ec5.zip |
| ✗ | Apple Watch Series 2 (38mm) | watchOS 5.1 (16R5577c) | October 9, 2018 | 1.3 GiB | 01e58cb941bd1ec1d122c8b89fbd1bd251c5f343.zip |
| ✗ | Apple Watch Series 2 (38mm) | watchOS 5.1 (16R5584a) | October 15, 2018 | 1.3 GiB | d382e3096c6457032f11cf1d70d36f41a455c4b5.zip |
| ✗ | Apple Watch Series 2 (38mm) | watchOS 5.1 (16R5589c) | October 22, 2018 | 1.3 GiB | a0bfc96240a519fd6ec1e972b036f702ca238863.zip |