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 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 4d789b99a5017da2ec801d4a610e909f6ba14c0b.zip |
| ✗ | Apple Watch Series 2 (42mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 45c059145d59c63ca354d9ada931dfd6147525e1.zip |
| ✗ | Apple Watch Series 1 (38mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 74559bc9373563921b99afc4c0015960fd74e6b1.zip |
| ✗ | Apple Watch Series 1 (42mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | a6be4fd7393b3c512f92c9cdcc4c9aa0a6036403.zip |
| ✗ | Apple Watch Series 3 (38mm, LTE) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 3ccd95a9935f64916702039f1a339494f74c3506.zip |
| ✗ | Apple Watch Series 3 (42mm, LTE) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 4a6700b5e610bc2559237c1fbfd742c7acd339da.zip |
| ✗ | Apple Watch Series 3 (38mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | dda3d66e26cf71b5f94ee1eed7775efef57ce038.zip |
| ✗ | Apple Watch Series 3 (42mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 2397d48902ef50a4ae1bc428816c5db0a0e730cc.zip |
| ✗ | Apple Watch Series 4 (44mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | ab50cc058bf47a97bbb5b85d77663f6a58dbaedc.zip |
| ✗ | Apple Watch Series 4 (40mm) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | e47845b9ea6f9c37083d83b42dc41bf286ee2ea6.zip |
| ✗ | Apple Watch Series 4 (40mm, LTE) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.4 GiB | 9af57196426016c10c2349539beaf1a653c613a0.zip |
| ✗ | Apple Watch Series 4 (44mm, LTE) | watchOS 5.3.4 (16U627) | December 10, 2019 | 1.3 GiB | 3cb24f3d7a727d13e2edc1325b4b478b7a60fd69.zip |