[General Topics] eaglesteve:
The procedure for moving from a jailbreak firmware to a new firmware is as follows:

If you wish to protect the application data of jailbroken application, then you should do an UPGRADE to new firmware. If on the other hand, you do not have any data of jailbroken application to bring over, then you are better of doing a RESTORE to the new firmware because this procedure will reclaim spaces previously used by the jailbreak application data.

If you want to do a restore,

1) Backup your device setting and data to iTune first.

2) Connect your iPhone to iTune, and click restore to new firmware. This will wipe the phone clean.

3) Then do a restore of the data and settings in iTune.

4) Rejailbreak.

5) Go to the Rock Application to automatically reinstall all the jailbreak applications you had previously. Hopefully by now all of them would have been revised to also work in the new firmware. If it does not work anymore, then wait for the developers to issue the version for the new version. (Cydia application developers are now already revising their application using the beta OS4.0 in anticipation of the OS4.0 release in June 22, so hopefully by then everything will be all system go)

6)If you need to use a different carrier, run the unlock program for that baseband.

If you want to do an upgrade, then backup is optional.

1) Connect your iphone to iTune, click upgrade button. All data on iPhone would be unaffected by this step

2) Rejailbreak.

3) Go to the Rock Application to automatically reinstall all the jailbreak applications you had previously.

4) If you need to use a different carrier, run the unlock program for that baseband.

In recently times, the same jailbreak program generally has become workable across all models (3GS, 3G, iPod Touch, etc), but sometimes a different jailbreak tool is issue for different model, so be aware. In anycase, they are all equally simple steps to carry out.

Whenever there is a new firmware, the hacking team will generally advice you to NOT upgrade first, but to wait for them to test their jailbreak tools before you use them. We don't normally have to wait for long before the new firmware jailbreak tool is available. OS 4.0 for example, is already jailbroken, so I expect that within the first week of OS4.0 being released, my 3GS would be running the new OS, jailbroken, and all stock as well as most Cydia applications running.

If Apple has been trying very hard to stop the jailbreak, they're doing a very poor job so far.

All models, other than first generation iPhone, will be able to use OS4.0 the day it is released, and jailbreak too.

I think in this aspect, Android suffers some disadvantage compared to iPhone. When a new firmware is released, not all handset could upgrade, unlike in iPhone, where every handset would be able to upgrade (first generation iPhone is the only exception so far). That's why so many Android handset today are still running old versions of firmware. I understand that Hero took a year to get its upgrade to 2.1 after 2.1 was released. This would never happen in iPhone where all capable handsets will get the update on the day of firmware release.

One fantastic aspect of jailbreaking iPhone is how jailbroken applications and data used by jailbroken applications are seamlessly carried over after switching over to the new firmware. The only thing users have to pray for is that all applications (both the App Store and Cydia) have been modified to work in the new OS. The modification work is usually done with the beta version of the OS before general release.

So, nothing to worry as far as iPhone is concern here.

I hope someone could help me understand the situation in similar level of details with Android firmware upgrade. Perhaps take Hero as an example if anyone of you guys have done it before. Walk through the step with us and describe how it's done, to give an idea for comparison purposes.

If you're into music and you don't want to jailbreak, you might want to consider using Pandora, Grooveshark or similar program. It is much much more than internet radio for music. Some of these programs lets you save the music to avoid having to repeat the streaming. If you're into saving music video from youtube and don't want to jailbreak, there are also applications in App Store that lets you do this. I know free MP3 are big things for Chinese users, and Nokia offers unlimited download in this country. Outside China though, there's lot of legal issue that we need to worry about doing such download. Are you into just Chinese music or also English ones? Depending on your requirements, Pandora (gerenally only for US users, so non-US users would have to use proxy server to use it) may not offer the kine of musics you want. Also, I got the impression that you can't get youtube in China. So the solution I suggested may not be feasible. I have however, come across a number of music download applications (can't remember now as I have long deleted them) that download Chinese pop musics from Chinese servers directly into iPhone. Unfortunately, this is a Cydia program so you do have to jailbreak the iPhone.