BigBoss issued a warning regarding the use of ZiPhone to jailbreak and unlock Apple's iPhone. In a nutshell, he says, "Don't use it", and points to several reasons for his position.

I didn't personally have any issues with ZiPhone either of the two times that I used it, but given the warning, the facts he cited, and the cases of bricked iPhones to which he refers, I may be using something else to jailbreak my 3G iPhone. BigBoss seems to suggest iLiberty (iLibertyX for Mac and iLiberty+ for Windows) or iDemocracy (Windows and Mac) as an alternative solution for jailbreaking/unlocking the iPhone, so I may be going with one of them instead.

One of the issues with ZiPhone, according to BigBoss, is that it downgrades your bootloader to 3.9 ("3.9BL"), rather than 3.9 fakeblank ("3.9FB"), as iLiberty does...

iLiberty+ does not downgrade your bootloader by default. It downgrades you to 3.9 fakeblank which is easily reversible and not dangerous. This is not the same thing as 3.9 used by Ziphone! Ziphone downgrades the bootloader to 3.9 automatically. If this process fails, you’re done. This process considered so risky that Apple does not do any bootloader upgrades in their firmware packages! They could have put a stop to all the unlocks when 1.1.2 came out by having the 1.1.1 to 1.1.2 firmware upgrade upgrade old bootloaders to 4.6 but they considered this too risky and did not do it! Ziphone does it anyway.

Regarding those who have already used ZiPhone, he goes on to say...

If you used it and your phone is working there is no need to do anything. You’re ok. If your bootloader has been downgraded to 3.9, you are also ok (if it worked). There are a million iPhones with 3.9 factory shipped from Apple. This article is intended to expose the risk in using Ziphone but once it is done, if it worked, you’re ok.

I only ran ZiPhone's jailbreak utility, and did not unlock the iPhone (I'm an AT&T customer and didn't need to do this). I posted a few questions in response to BigBoss' warning, asking the following...

Assuming that I will be getting the new 3G iPhone when it is released, and also assuming that I will be selling my current iPhone…

If I do a restore of my current iPhone using iTunes (I found a guide I’m going to use to secure wipe it first), will it be in working order and ready to sell to the buyer? Is there anything else that I need to do? Will I have issues with this, since I used ZiPhone first, then restored, then used iDemocracy (seems like you are already saying “no issues” to this question)?

Also, what if I wanted to jailbreak the iPhone prior to sending it to the buyer…could I restore, and then use iDemocracy (I’m a Mac user) to do this without any problems?

If all I did was jailbreak my iPhone, was the bootloader downgraded by ZiPhone? I am an AT&T customer, so there was no need to unlock the phone. I only wanted it jailbroken.

Hopefully, he will respond to me and let me know whether or not my bootloader was changed, and if I can successfully jailbreak the iPhone using iDemocracy or iLiberty in the future. Most-likely, when I sell the iPhone, I will simply secure-wipe and restore it, leaving the jailbreaking/unlocking to the buyer. That'll be one less headache for me to worry about.

UPDATE: 19 June 2008 at 2:25PM

BigBoss replied to my question regarding the bootloader being changed...

Probably not, it probably is fine. And to add to this point, that means ziphone is perfectly safe to use on a touch, in my opinion.

Note that he says he is of the opinion that ZiPhone is probably fine if you want to jailbreak an iPod Touch, since the Touch is not a phone and does not need to be unlocked.

Given this additional information, it would seem to me that using ZiPhone to jailbreak is fine, while using it to SIM unlock the iPhone could cause issues (and definitely downgrades the bootloader).

UPDATE: 19 June 2008 at 3:21PM

BigBoss had another reply regarding one of my earlier questions:

After a restore, the jailbreak is gone. So you’re back to square one as far as jailbreak is concerned. Ziphone could even be used for jailbreak alone, if we could trust that there wasnt a bug in the command line parser that would start its unlock routine even though you didn’t request it.

As for the sim unlock it is a different story. This is where the real danger is. If the boot loader is already downgraded, and it is downgraded successfully, the danger has passed and you’re good to go.

So, jailbreaking via ZiPhone, and then restoring will put you back to normal. Using another jailbreak tool will jailbreak it again, but ZiPhone's previous jailbreak will have no effect on the outcome, since it has been reversed/undone by the restore.

SIM unlock, however, is a different story, since you have downgraded the bootloader, but it shouldn't be an issue anyway, so long as everything went well and the iPhone worked fine after ZiPhone was used to SIM unlock the phone.

UPDATE: 19 June 2008 at 4:52PM

I just installed Baseband Info and it ran a query of the bootloader on my iPhone. It still has version 4.6_M3S2, so ZiPhone didn't touch the bootloader.