Developing for a jailbroken iPhone, A to Z (iPhone 3.0)

CalveYard, sorry, for some reason Akismet got your comment. I’ve been having this same problem trying to test on my 2.2.1 iPod Touch, and I’m trying to figure out what’s up. Stay tuned.

Huh, glad you got it to work, Rich! I realized that the #! /bin/bash line might have gotten lost since it was on a line with non-code text, so I bumped it down in case that was the problem.

All others, don’t worry, I’m still trying to figure out the issues. We’ll see what the forthcoming 3.1 release holds.

Did you restart the computer and the phone? Sometimes that can be the difference.

Falk, the .ipa has a filestructure of its own. It IS just a zip file of this filestructure, but what I don’t know is exactly how the internals work. Try unzipping an app you already have (drag/drop it out of iTunes onto your desktop, it’ll only copy, not move, then rename to .zip and unzip), then try replacing the .app in the Payload directory and rezipping. I have a feeling it’ll have the same artwork as the app you unzipped (you never replaced the itunesartwork file) but it may work to distribute your own app. What I’m not sure of is what that .bin does. It may be a hash of the payload, preventing this idea from flying. It may be that you can just delete it, try it.

What’s guaranteed is that your target device (your tester’s) will have to be jailbroken and have Installd Patch installed. Or you can manually fakesign your binary with ldid on the phone, then transfer it back off, as is done for cydia distribution, but that’s a different article.

Let me know what you find.

efes: I was actually considering going down that same road since soon enough I’ll have some apps I want to release officially. I’m not EXACTLY sure how to go about it, but I think that you can sign up and just follow all of apple’s standard procedures for provisioning your device(s). That involves going online to get a code signing identity, generating a provisioning profile, and so on. I don’t believe that any on device jailbreaking should prevent that from working. However, the Xcode hack in this article is relatively ghetto – it has a lot of bugs for some reason, and I’m not sure how well it’ll play with an official provisioning profile (since it doesn’t even play that well without one yet). My suggestion would be to NOT patch Xcode yet, and to try following Apple’s direction but on your jailbroken device. The good thing is that the Xcode patch is always reversable – if it messes you up, reinstall the SDK.

Falk: Thanks for the link, I’ll check it out and wait for an update from you. There’s actually a link that may contain information you want cited as a source in a post I’ve already written. I just haven’t published it yet because of all of the bugs still plaguing this post. I wanted to sort this out before I began offering support for the new post. That said, I may just post it anyway, because it’s relevant on its own and I’m not sure when I’ll be able to figure this all out (although it’s nearly the weekend, hope is on the horizon [literally]!). <- I have to take pride in those properly-balanced perens. Sorry. Moving on. Mars: Have you tried to break Xcode before? For the 2.2 SDK, there was a method where you added a build phase to the Xcode build process that would use that script (which you had to download from a website whose location I forget) to generate falsified entitlements for the device. It was no longer necessary as of the latest method for 2.2, and is not a current step in this SDK 3.0 method, but you may have hangover from a prior attempt to get this going on 2.2. My suggestion is, if you don't remember where you found that tip, and you don't know how to retrace your steps to remove it as a build phase, fully uninstalling the SDK and reinstalling from the fresh 3.0 download should do the trick. Let me know how it goes.

Mars: Yes, if you can, that should do the trick.

efes: Ahh, you do raise an interesting point. I have never provisioned my devices, so I didn’t realize that you had to do a full restore with a provisioned image. So as I see it, you have two potential options, assuming both work: 1. provision your device, use quickpwn. I don’t think that quickpwn works with 3.0, and I’m not sure what the install mechanism of redsn0w or purplera1n are (besides, I think purplera1n is 3G S only. 2. make a provisioned image, save it out to a .ipsw like you would download and restore in iTunes (can you do this?) then use pwnage tool on THAT provisioned image. Assuming you can do them, either should work. Those are just ideas, though.

mars again: That’s the site I remember. I don’t think I’ve ever figured out how to undo adding a new build phase, but I’ve also never really tried. I can look into it later (probably tomorrow, I won’t be home for another few hours, long commute), or if you don’t want to wait (I know I wouldn’t) you can try uninstalling/reinstalling, which should give you a fully fresh platform.

mars: You say that like you expect me to MIND you helping the other commenters :P. Good to know about deleting scripts though. And yes, I’ve never heard that hype myself, but I can tell you for certain that this method doesn’t affect the vitality of the device as either an iPod or a phone (depending on which hardware you use). I can’t speak to ACTUALLY provisioning a device the official way – perhaps that DOES cause some headaches with normal use, but I’d be willing to bet that that’s not true either. To be very specific, I’ve tried this with both my devices (iPhone 3G and iPod Touch 1G) on both OS 3.0 and 2.2, and both work fine as a phone/ipod still – they’re my personal devices, I don’t use them exclusively for development.

Mars: The new 3GS is actually a SIGNIFICANTLY better device than the iPhones to date (or iPod touches). It uses an Arm 11 chipset instead of an Arm 9, which is leaps and bounds better as a processor – not just in speed. The camera IS nicer, it takes good, clean (if not high res) video, and the sounds is nice. I absolutely would have bought it, IF ATT didn’t decide to give me a giant middle finger and charge an extra 200 if you have a 3G. I’m not spending $500 on it, so I’m waiting for the next revision. And you ARE right, there arent many new features. It’s less that the new phone is unbearably wonderful and more that my 3G is unbearably slow.

Everyone: zim here has a few suggestions that should make full on debugging work with the 3G. I’ll post them once I’ve verified that they work for this setup (they should though). I’ll also try to test them on my 2.2 device and see what I get. They should solve that problem too, but we’ll see.

Your understanding is correct: C is procedural, but C++ and Objective-C are both object oriented. I don’t have a ton of experience with C++, but I use both C (for programing Arduino) and Obj-C (for iPhone) all the time, along with lots of other languages for personal, work, and school reasons. In terms of which of those two choices I’d opt to learn, I’d pick Obj-C, but there are lots of important reasons: first, lots more things use C++ than use Obj-C. In fact, Apple is the only platform that I know of off the top of my head that uses Obj-C heavily. You can program other things in Obj-C, it’s not like it’s off limits, it’s just that nobody really does. So off the bat, C++ is more useful in the world. The important caveat to this is that, of course, C++ isn’t more useful in MY world – I’ve never had to use it, while, on the other hand, I use Obj-C all the time to code for iPhone, so I learned Obj-C instead, that’s that.

Second, I find that, while the syntax of Obj-C is totally different from that of C# is totally different from that of C++, getting used to new syntax is significantly less of a hurdle than getting used to object orientation. I liken it to cars – a pickup truck is a VERY different animal from, say a Lambo, just like Obj-C is VERY different from Matlab’s M (another OOP language I use heavily at work and school). That said, (in the US anyway) once you have a class C driver’s license, you can drive either, and the individual vehical just takes a bit of getting used to. (In this analogy, C is kind of like a bicycle or Vespa – it’ll get you there, and you even have more maneuverability, but damned if it won’t take you a while).

Does that make sense? I know procedural languages and a range of OO languages from barely OO at all to BLEEDING OO (Obj-C). Once you know one, it’s just a matter of getting used to the others, so do whatever’s most useful for you NOW.

As an aside, another idea that’s interesting is that, typically in an academic setting, the most useful language is picked as the one to teach students. That used to be C or C++ since those are common and foundational. Now, however, we’re starting to see engineering programs (IE mine at BU) using Matlab since most every engineer uses that in work at some point these days. Comp sci programs use java, because lots and lots of scientists use Java to model things, and some are using Apple’s course in Obj-C, since theres a huge market for it even if it’s used by only one device company.

Basically, the point is, do what you want, knowing you’ll almost always have to adapt later anyway.

I know what you mean, for sure, although I don’t think it’s a terribly accurate depiction: Plenty of open source and cross-platform projects use C++. I think the underlying idea that you’re getting at is that Obj-C is “cooler,” which I agree with even though there’s very little basis for that 🙂

And BU = Boston University, EE student, yeah.