Game crashes on start on mobile

Unity Engine
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1

iPhone 4s:
The game plays fine in the editor. The Xcode build actually completes, followed by the play test. The last line the console prints is that the engine is initializing (v 5.3.2p2) and then I get a “Lost Connection to iPhone X” message. No errors whatsoever, no memory warnings that I can see.

2 days ago, the game was playing fine on iOS. I was actually in the process of optimizing it, and even during the most demanding moments, it wasn’t receiving memory warnings.

I’m pretty sure the only things I’ve changed are unticking raycast target on several UI elements, removing some graphics raycasters on certain world canvases, removing some graphic scalers as well.

I tried setting everything the way it was before I made the changes, seems like I’m getting no luck. Most likely I’m forgetting a change I made.

I’m not using versions control of any types and I’m unable to rollback to compare versions. Any ideas what could be causing this?

EDIT :
Works fine on iPhone 5s, doesn’t work on 4s. After deeper inspection, I see that, at launch, the game was soaking 96% cpu usage on the iPhone 4s, probably causing the crash. Yet no memory warnings on Xcode.

What could cause a game to change so drastically? I’ve done nothing major, pretty sure I haven’t touched the player/quality settings since the last working version, and anyways I’ve recompiled with every settings reverted to default. 95% sure the only things I’ve changed are graphic raycasters/scalers. Most likely not the issue, as reverting these didn’t fix my problem. I’m clueless.

Supporting 4s is needed in my case. How would you guys handle this? What would you check next? I’ve rebuilt 30ish times in the last 2 days and that’s painful work with my dinosaur computer. I can’t seem to isolate the issue. Removing X, Y, and the game works. Removing A, B, the game also works, although they’re completely different and unrelated. Hence it feels like a memory issue. The very same setup was working just fine 2 days ago.

It also feels like both the unity and the Xcode build times have increased significantly. That, or I’m going mad.

2

Maybe memory issues but could be rendering or something else. Try doing a build for 4S with all the textures “Max Size” reduced to a minimum and parameters in QualitySettings - reduce those to minimum levels too. If that works, watch your memory levels and step them back up slowly. XCode doesn’t spew out any errors? Check your active console and do some Debug Logs.

4s is working fine for me (my base device that I do test with).

Unity now builds all the Bitcode versions, so yes it does take longer to build in XCode, only thing that will help is a faster machine and an SSD. More info: http://forum.unity3d.com/threads/unity-5-3-x-build-size-increase-faq.383533/#post-2512702