It's certainly possible to develop on a Windows machine, in fact, my first application was exclusively developed on the old Dell Precision I had at the time :)
There are three routes;
- Install OSx86 (aka iATKOS / Kalyway) on a second partition/disk and dual boot.
- Run Mac OS X Server under VMWare (Mac OS X 10.7 (Lion) onwards, read the update below).
- Use Delphi XE4 and the macincloud service. This is a commercial toolset, but the component and lib support is growing.
The first route requires modifying (or using a pre-modified) image of Leopard that can be installed on a regular PC. This is not as hard as you would think, although your success/effort ratio will depend upon how closely the hardware in your PC matches that in Mac hardware - e.g. if you're running a Core 2 Duo on an Intel Motherboard, with an NVidia graphics card you are laughing. If you're running an AMD machine or something without SSE3 it gets a little more involved.
If you purchase (or already own) a version of Leopard then this is a gray area since the Leopard EULA states you may only run it on an "Apple Labeled" machine. As many point out if you stick an Apple sticker on your PC you're probably covered.
The second option is more costly. The EULA for the workstation version of Leopard prevents it from being run under emulation and as a result, there's no support in VMWare for this. Leopard server, however, CAN be run under emulation and can be used for desktop purposes. Leopard server and VMWare are expensive, however.
If you're interested in option 1) I would suggest starting at Insanelymac and reading the OSx86 sections.
I do think you should consider whether the time you will invest is going to be worth the money you will save though. It was for me because I enjoy tinkering with this type of stuff and I started during the early iPhone betas, months before their App Store became available.
Alternatively, you could pick up a low-spec Mac Mini from eBay. You don't need much horsepower to run the SDK and you can always sell it on later if you decide to stop development or buy a better Mac.
Update: You cannot create a Mac OS X Client virtual machine for OS X 10.6 and earlier. Apple does not allow these Client OSes to be virtualized. With Mac OS X 10.7 (Lion) onwards, Apple has changed its licensing agreement in regards to virtualization. Source: VMWare KnowledgeBase
You can use the UIDevice class like this:
NSString *deviceType = [UIDevice currentDevice].model;
if([deviceType isEqualToString:@"iPhone"])
// it's an iPhone
Best Answer
While Jasarien is correct in that you cannot rollback the baseband once a device has been flashed with a specific baseband (in the general case, anyway), you can still usually downgrade the firmware. This will, however, not downgrade the baseband and unless the newer baseband is compatible with the old firmware (unlikely) you'll be left with a device that cannot connect to the cellular network or perform other networking functions, possibly including not being able to connect to a Wifi network. If a lack of networking capability would leave you unable to test your application, then you will need to find someone who still has a device on 3.0. Additionally, Apple has Compatibility Labs if you are near their Cupertino campus.
If you do still want to roll back the firmware, you can do so, but you'll be greeted with an error number (probably error 1015). This in itself isn't a problem - this just signifies that the baseband flashing failed - but you'll need to use some third-party software to kick your iPhone out of restore mode.
Unfortunately, if your device is a iPhone 3GS, you're out of luck. Apple stopped signing firmware updates for 3.0 and 3.0.1 quite a while ago, and unless you prepared ahead of time to ensure that you could retain your ability to downgrade to 3.0 (which sounds unlikely, if you're asking this question), you're up a creek.
If you need more detailed downgrading instructions, I suggest you take a look at one of the many blogs with instructions (a small sampling of which are listed): http://www.iphonedownloadblog.com/2009/09/15/downgrade-iphone-31-to-30/ http://www.blogsdna.com/3911/how-to-downgrade-iphone-3gs-31-to-30-os.htm