iPhone 2.0的破解雖然陸續傳出好消息（已經成功jailbreak了？），但畢竟還沒有正式完整的方案出來，因此，您現在絕對不可以將您的iPhone升級到2.0喔，除非，您用的是未經過破解的iPhone或iPhone3G(內建)，但如果我還是不小心被強迫升級到2.0(自動更新打勾)那怎麼辦呢？和過去一樣短暫變磚嗎？

別擔心，來自於sleeper.net友站的消息，bigboss已經推出2.0降級為1.1.4的方法囉，原文提供的方式如下：

Here are the steps for a successful 2.0 to 1.1.4 downgrade for those of you that updated to 2.0 and realized what a mistake it was. (Thanks goes to Geeb for finding the iTunes 7.5 solution, Thanks goes to Crumpx for the pwnage method). Note that this has been performed on a PC.

Ok, so you updated to iTunes 7.7 and then installed 2.0 and you’re stuck. Here are the steps to downgrade to 1.1.4. Note that the result of this guide will be that you will be back to 1.1.4 version of firmware with baseband of 2.0 (4.05.04_G).

1) The first problem in your downgrade is that you probably are getting error 20 in restore mode and error 160x in DFU mode. This is due to iTunes 7.7.  So, you now you need to uninstall iTunes 7.7 and install iTunes 7.5. Make sure after your iTunes 7.7 uninstall you reboot your pc as it requests you to. **OSX users, see note at bottom of page to downgrade your iTunes.

2) Now that you have  iTunes 7.5, you will still have the DFU driver for 7.7. This is good and will allow the process to work. Put your phone into DFU mode using the DFU steps.

3) Restore using iTunes 7.5. You will get an error like 1011, 1013, 1015. This is normal and expected. An error 1601, 1602, 1600 or anything else is not ok.

4) Once you get error above, leave iTunes open and kick your phone out of restore mode. I recommend just loading winpwn(PC) or pwnage(MAC) and pwning the device at this point. If pwnage fails to work, you need to restore your phone again. You should be able to use normal restore mode, however. Other ways to kick out of restore mode may be ibrickr, jailbreak 1.1.2 (boot phone), iLiberty+.

5) Once completed, you have a pwned device with baseband 4.05.04_G from firmware v2.0.

6) To get back to 04.04.05_G (1.1.4 baseband) load bootneuter. If you don’t have this, install it from installer. Run bootneuter with Neuter, 4.6, and unlock. When it’s done, you will have an unlocked 04.04.05_G right back where you started.

Note:
If you are on OSX and want to attempt to downgrade your iTunes, you can try these steps:

Load up Terminal and type the following:
killall iTunesHelper
rm -r /Applications/iTunes.app
rm -r /Library/Receipts/iTunesX.pkg
rm  ~/Library/Preferences/com.apple.iTunes*
rm -r /Applications/iTunes.app
rm -r /Library/Receipts/iTunesX.pkg
rm  ~/Library/Preferences/com.apple.iTunes*

今天的iPhone資訊爆炸，接連幾篇的文章已經讓娃娃魚身心俱疲，所以就暫時不提供中文翻譯了，目前iTunes內尚未提供2.0韌體的自動下載，因此若您擔心會不小心升級到2.0變磚的話，請記得將自動更新的選項取消喔，再三的叮嚀只希望不會有人發生變磚的意外，不過現在既然已經有了降級的護身符，我想也就不需太擔心了。

原始消息來源：2.0 to 1.1.4 Downgrade