backsn0w, tethered jailbreak - closer look

B737 said:

But this is a tethered jailbreak, like back in the early days!

[snip]

but i feel as though the tethered 'feature' of the jailbreak has been understated...

thoughts?

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It's a tethered jailbreak only for the 3rd gen Touch, and recently purchased 3GS with the new bootrom. My guess is it hasn't been discussed much because it affects only a relative minority of jailbreakers.

B737 said:

Im surprised this hasnt been discussed in more detail. From reading, there is a tremendous outpouring of good feedback from the blackra1n RC3, and rightfully so...

But this is a tethered jailbreak, like back in the early days! phone dies and you're on the road, you're SOL! i was just about to j/b a friends 3GS today (that was purchased today) and i thankfully aborted just before pushing the button. i was bummed!

theres no bones about it, geohot is a genius and this work in particular is amazing.

but i feel as though the tethered 'feature' of the jailbreak has been understated...

thoughts?

Click to expand...

Not true for most devices, only the newest iphones with the new iBoot. I guess in the end someone will figure the solution to that out.

But for this community? 99% at least already have their iPhones and they do not have the new iBoot, so the JB/unlock is untethered.

I've been jailbreaking since it first popped up a few weeks after the original iPhone's release. But I'm not entirely clear on what a tethered jailbreak actually is. Apparently I've done one before, but didn't realize it. What's the difference?

I believe it means that if the phone is powered off then on reboot it will have forgotten it was jailbroken, so you then have to reconnect to your PC and rejailbreak.

I am not sure if this only happens when the battery runs right down, or also when you power it off yourself.

If you shut off the phone or restart the phone, it must be connected to the computer in order to restart.

Moi un Mouton said:

I believe it means that if the phone is powered off then on reboot it will have forgotten it was jailbroken, so you then have to reconnect to your PC and rejailbreak.

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"Rejailbreak" isn't exactly the right word. As I understand it, when the iPhone (or iPod touch) boots up, it checks the firmware to make sure it hasn't been modified. Untethered jailbreaks make the iPhone skip this step, allowing it to boot jailbroken firmware. Tethered jailbreaks need an external device, usually a computer, to insert a command so the iPhone can boot jailbroken firmware. So the jailbreak is never erased or "forgotten," just the ability to run it.

dhlizard said:

If you shut off the phone or restart the phone, it must be connected to the computer in order to restart.

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To be more precise, it's when you power off (whether it's because the battery runs out or you shut off the phone manually), or if you have to reboot, like when your phone freezes, or is sometimes required after you install a Cydia package. Most packages only require a respring (soft restart), which can be done without connecting to a computer.

Thanks for the clarification guys. And the initial iPhone jailbreaks used this tethered method? I really don't recall that. Very interesting.

Night Spring said:

"Rejailbreak" isn't exactly the right word. As I understand it, when the iPhone (or iPod touch) boots up, it checks the firmware to make sure it hasn't been modified. Untethered jailbreaks make the iPhone skip this step, allowing it to boot jailbroken firmware. Tethered jailbreaks need an external device, usually a computer, to insert a command so the iPhone can boot jailbroken firmware. So the jailbreak is never erased or "forgotten," just the ability to run it.

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but just hooking it to a computer gets past that hangup? any computer? or do you need to run blackra1n again? that is the point that is never clarified, everyone just says that you need to hook it to the computer when you reboot. fortunately, i have the older bootrom ao i'm not in that boat, but who knows what the future holds.

scottuf said:

but just hooking it to a computer gets past that hangup? any computer? or do you need to run blackra1n again? that is the point that is never clarified, everyone just says that you need to hook it to the computer when you reboot. fortunately, i have the older bootrom ao i'm not in that boat, but who knows what the future holds.

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Oh, sorry about the confusion, yes, you do need to run blackra1n again -- that inserts the command I was talking about. But blackra1n is a standalone executable file that's easy to carry with you on any portable storage media. It'd fit in a floppy drive, if you can find a computer nowadays that reads floppys.

I've rebooted my phone several times and the blackrain hack and unlock is still there. I wonder if the same is the case if the battery runs out? I think its a different thing.

Just in case though how do I go about getting a tethered unlock?

Thanks,

The tethered jailbreak is only needed for very recent 3GS handsets that have got the updated bootrom

Night Spring said:

Oh, sorry about the confusion, yes, you do need to run blackra1n again -- that inserts the command I was talking about. But blackra1n is a standalone executable file that's easy to carry with you on any portable storage media. It'd fit in a floppy drive, if you can find a computer nowadays that reads floppys.

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that's what i thought, but thanks for making it official

Night Spring said:

Oh, sorry about the confusion, yes, you do need to run blackra1n again -- that inserts the command I was talking about. But blackra1n is a standalone executable file that's easy to carry with you on any portable storage media. It'd fit in a floppy drive, if you can find a computer nowadays that reads floppys.

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Don't forget you need to carry around the USB cable too. Not very convenient...

FastangV6 said:

Don't forget you need to carry around the USB cable too. Not very convenient...

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Depends on what you are doing. When I go to work I always take my laptop, so tucking a USB cable into the laptop bag is no hardship.

Maybe I'm in the minority here.....but I'm thinking of getting a current 32gb 3Gs before Apple closes the hole on even the tethered jailbreak.

I've already got a 16gb 3Gs with 3.1.2 JB'n running, and it's 99% everything I really need ATM for a phone. It's very stable, and does everything (save for Flash like we all want). With a new 32gb, I'd just run it at 3.1.2 with the tethered JB until it just dies. It'd have to be a very compelling Apple OS upgrade to cause me to go through that.

If a 'respring' doesn't require the tether, which it doesn't look like it does, then I don't really see an issue for me with it requiring the tether to do a hard reboot/off/on sequence. I only do that maybe once a week. Respring several times a day though....

Moi un Mouton said:

The tethered jailbreak is only needed for very recent 3GS handsets that have got the updated bootrom

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Which I have and I am just pointing out that a reboot doesn't break the JB or the unlock. It can break the wifi if I have a sim inserted for some reason though.

I haven't tried letting the battery drop, but I will cross that bridge when I come to it. I hope there is a tethered version soon or better still O2 will unlock my phone legit as my contract has expired!!!

Ori said:

Which I have and I am just pointing out that a reboot doesn't break the JB or the unlock. It can break the wifi if I have a sim inserted for some reason though.

I haven't tried letting the battery drop, but I will cross that bridge when I come to it. I hope there is a tethered version soon or better still O2 will unlock my phone legit as my contract has expired!!!

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Just curious to know how you have a 3GS less than a month old AND an expired contract

Moi un Mouton said:

Just curious to know how you have a 3GS less than a month old AND an expired contract

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Probably bought it "barely" used or paid full no contract price.

I just bought 2 "barely used" 3GS phones with older bootrom (for untethered jailbreak convenience) and my contract is about to expire. Of course being in the US, I can't get it unlocked, but I like the idea of a couple of 2 month old phones, with 10 months of warranty, and no contract.

Had I waited for my renewal date, I would have gotten 3GS phones with tethered jailbreak bootrom.

Ori said:

I've rebooted my phone several times and the blackrain hack and unlock is still there. I wonder if the same is the case if the battery runs out? I think its a different thing.

Just in case though how do I go about getting a tethered unlock?

Thanks,

Click to expand...

If you've rebooted and it starts without re-running blackra1n, then you have an untethered jailbreak and don't have to worry about tethered-ness.