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 2 (38mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | 56fc0a75b9a0ef0d34e1dde4a63c230532caad0d.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | f89e4ef68e2f5f7231a968b53964036914fd63ec.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | 6fd10a252b94f13dc3f86f6a0733eafaa41f07b7.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | 1be05835ea4da51fbd6f78d55c19461fa68b220e.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | bde079186f81823ef60e1ecd69a279d5a63a19d3.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | cdccc6fec7a99d6765e6bef2456b8aeee9365373.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | 7c1d2c7a9638309861133734b1f1e07f4ebf7f32.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | a101b9230f3ba2c652c8b84945b53ef0295743a0.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | baa1a91e958da9211f757e1e471e714d3d836e19.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | 13686c2f3e6bc077da5381abd9cbe446b0d6fa8b.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.4 GiB | 1dd30d61f7605e4cbfcfdb65cd9838409931b129.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.3.3 (16U620) | October 29, 2019 | 1.3 GiB | 04576e7f135a8b2428c7b59c8e01a85ab5ef7bd0.zip |