IPSW Portal

Choose aProduct→Choose aPlatform→Choose aVersion→ClickDownload

Download 4.0 (15R5371a) for Apple Watch Series 1 (42mm)

Version:	4.0
Build:	15R5371a
Signed:	No
Size:	0.29 GB
Release Date:	2017-08-28 16:53:49
Upload Date:	2017-08-26 17:07:28

Secure download directly from Apple's servers