Slides: https://github.com/saagarjha/Presentations/tree/main/CocoaHeads%20%2B%20SLUG%20June%202026.

But, also, a GitHub repo for a new project fo mine: https://github.com/saagarjha/DeviceSupport. Think unxip but for “copying shared cache symbols”. It is currently slop as a proof of concept so I could demo it but I plan to clean it up soon

https://federated.saagarjha.com/notice/B7LCZIh1mzdj3AllNg

In my tests, with good internet this downloads iOS symbols several times faster and watchOS symbols at least an order of magnitude faster. Think 30 seconds rather than minutes

@saagar Interesting. In the iOS symbols case you're comparing "copy shared cache off device" versus "extract shared cache from ipsw/ota on apple CDN" right. But isn't the watchos shared cache already downloaded from apple CDN, why is this approach an order of magnitude faster?

@jasonmolenda Downloading from the CDN for watchOS usually hits an error of some kind and it falls back to grabbing from the device

@jasonmolenda Yeah OK I looked into this a little more and some builds are just inaccessible?

GET https://download.developer.apple.com/Developer_Tools/watchOS_23T240/watchOS_23T240.dmg with virtual auth → works
GET https://download.developer.apple.com/Developer_Tools/watchOS_23T570/watchOS_23T570.dmg → fails with virtual auth (no cookie returned) and grandslam (403 Forbidden)