I was going through the JB forum and although I advocate for the jailbreaking of IOS I felt like someone needed to put something more comprehensive about the security and risk associated with it. Since the majority of us here have little to no sight handy it is super important that anyone wanting to liberate their IOS device does so with a bit of an understanding and some recovery tips.
When you JB an IOS device you are enabling the super user account "root" which is disabled for VERY good reasons after IOS finishes installing itself. This user account has 100% access to do anything like delete system files, allow remote access and so on. For an example, every single IOS device root account has the password "Alpine", and once your device is jailbroken the SCP protocol is allowed.
If someone were savvy enough they could quickly grab your IP address and access your device and steal whatever information from it or do whatever they wanted to it when you connect to any Wi-Fi network they are also on. If you are dead set on doing this you will need to learn a little bit about using a terminal, like PuTTY or the Mac terminal, connect to your device using it's IP address, the username "root" and password "Alpine" and issue the following command:
passwd root 123456
That would set the password to 123456 which although insanely insecure is better than the same thing as everyone else. You can change "123456" to whatever you want it to be, just don't forget what it is because you'll need it later on in your JB life - trust me.
That pretty much locks your device back down and from there on out you'll be as secure as you were before the jailbreak process. Since the root account has to be enabled and Cydia (the app store that comes with a JB) uses several components that are already installed you have to be super careful when uninstalling things from Cydia in order to not crash your device. There are a lot of things that come already loaded in Cydia and if you remove one of them it may delete a required system file instantly turning your IOS device into an IOS brick. Depending on the component that is in question it may require spending some time in the Apple store waiting for someone to pay attention to you on those God awful stools while little people run around touching everything and rude people invade your personal space - not really worth it LoL.
All of that being said and done, there are still a TON of risks involved. The most recent Pangu jailbreak released for IOS 9 up to 9.02 does work, BUT a new term has arisen from this particular tool - the BLOD (Boot Loop Of Death). Yes, Pangu's team has brought the BSOD's cousing to IOS devices... There are quite a few articles out there on how to avoid the BLOD or how to recover from the BLOD, unfortunately nobody seems to be warning folks about it. In my case I am just returning to IOS from Windows Phone (8, 8.1 & 10) and was eager to get BiteSMS, Winterboard and a ton of my old tweaks and apps back that I had missed for some time. As it turns out you get Cydia, but most of the tweaks and utilities are not ready, this includes my 2 favorites I just mentioned. In an attempt to get Winterboard working I accidentally missed a step and I'm pretty sure I did something wrong running Pangu in the first place.
Like always I did my backup to iTunes and then tried to restore the device, BUT no matter which of my 6 PC's I connected to the process would only go so far and then say "An unknown error has occurred", meanwhile I was stuck in the BLOD, but not the one that's easily fixed. For some reason the faulty JB or manual install of Winterboard.deb really screwed something up. Putting my iPhone 6[s] Plus in DFU didn't work, recovery mode didn't work and disabling Cydia tweaks during boot didn't work (I'll give instructions on all of those at the end of this post no worries), but after 27 hours of BLOD I found a program called "Reiboot" that actually worked. Yes, I did get it fixed myself, but I've been doing this kind of stuff for a long, long time and I personally know a few of the dev guys involved in the JB world so I kind of have a great pool of resources that the average end user doesn't get with a JB.
Things to take into consideration before jailbreaking your IOS device are the stability of the tool being released, the Pangu IOS 9 just isn't worth it at all. You also want to take things like how recently your device was backed up into account, if it's been longer than "I just did it" then it's been longer than acceptable. Not to mention your power infrastructure and weather conditions. I've had to walk tons of people through recovery because they decided to jailbreak during a lighning storm or something like that. Cydia will still be there for all of us when the weather clears up, so don't make that mistake. Finally, do some research online about what is happening to other jailbreakers before running it. Hd I listened to my own advice I would have easily skipped the whole 27 hours of BLOD and just enjoyed my device as is like I am right now.
In the end having a jailbroken device is pretty awesome and I can't wait until the next Apple vulnerability is discovered and we can install Cydia apps with ease. Even when we do all of our homework and research sometimes things can just go wrong though, so here are some tips and tricks to hep you get back into action. You may need a sighted person to assist you, but I'll try to make it as easy as possible for anyone to just independently do it all.
Since the dawn of time holding down the Home and Power buttons for about 30-40 seconds has been able to put most iDevices into "Recovery Mode". That's the one where the screen shows the iTunes log with a USB cord. Usually this is all you need to connect up to iTunes and restore your device, but beware this will wipe EVERYTHING off of your device and you'll have to start all over.
Sometimes that just isn't what iTunes or your device is looking for so there's DFU mode. This is a hybrid boot state that gies iTunes and the IOS firmware a little bit more wiggle room to do pretty much the same thing. Again it's going to wipe EVERYTHING out, but this one may take some practice. Hold down the Home and Power buttons for around 10 seconds and keep the Home buton pressed down but release the Power button. Keep hoding it for another 15 seconds and although your screen will be black you're now in DFU mode.
If you end up with the BLOD after running the Pangu Jailbreak or after installing a Cydia app/utility/tweak then hold down Home and Power for about 8-10 seconds and release them but then hold down the Volume Up button until IOS actually starts up. Technically as soon as the white Apple logo appreas you need to let go the Home/Power and start holding Volume Up, but if you have no useable vision then 8-10 seconds is pretty easy to count out. You might need to try this one a few times, but it basically disables all of the Cydia stuff, so if you installed the "crashyoudevice" app and it did just that, then you can boot with this method and then open Cydia and uninstall that app. No data lost, no starting all over!
There's also always the Windows program I mentioned before Reiboot, and I believe there is a Mac version too but I did it on PC so that's all I can swear by at this point. This program somehow, magically seems to get devices out of boot loops and recovery loops pretty well. It's how I fixed my most recentIOS brick move!
Again, I'd like to emphasize the fact that I whole heartedly endorse and encourage jailbreaking your IOS device. I also want to make sure it goes as smoothly as possible for anyone considering it. I have installed countless JB features and can't wait to see who comes up with a 9.1 JB so I can get back in the swing of things.
If you have a JB crisis and you need help you can feel free to hit me up on Twitter @t1ki and I'll be glad to lend whatever help I possibly can. Enjoy your liberated device and just be safe.