iPhone 4 Allows for Baseband Downgrade

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Posted July 16, 2010 at 5:02pm by iClarified

The iPhone 4 allows for the downgrading of your baseband during firmware downgrade but unfortunately the baseband is signed even stricter than SHSH blobs.

According to MuscleNerd you can't use TinyUmbrella-like backup of signed BB blobs because they're unique *per restore* (!!)

the blobs are only good until the next time the baseband reboots. Then the nonce changes and blobs worthless :(

MuscleNerd hopes that there's a flaw somewhere in the iPhone4 at+xnonce stuff which will allow the Dev-Team to circumvent Apple's security measures.

Also the iPhone 4 Bootloader and Bootrom has yet to be explored for exploits that might allow baseband downgrades.

Currently this feature is still a welcomed one for developers who were previously forced into a baseband upgrade when testing out beta firmware. Now they can restore back down and get back to the older baseband.

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krackerns - July 16, 2010 at 5:46pm

Hi Guys, I am not a developer but with programming for years... I am just curious if the dev team could find a way to mimic apple's signature in signing for Iphone downgrade. (legally though, so that no one will get in trouble) In this way, we don't have to keep on upgrading Jailbreaks and unlocks... everytime we accidentally upgrade our Iphone to higher baseband or versions.. :) Just a thought guys! Kudos to Dev team for your effort! Greatly Appreciated!

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krackerns - July 16, 2010 at 5:56pm

And if a new safe unlockable upgrade will be available from the dev team, then we always have the option to upgrade it. This will help us get out of a stuck, accidentally upgraded Iphone from using it with other Phone Carrier.. :) If dev team can mimic Apple's signature in signing for Iphone downgrade.. :) In this way, we dont have to wait for an unlock for the latest version. ;) Just a thought! This sounds pretty remarkable and I know this is not easy but I hope dev team can find a way! Kudos GUYS! Keep up the Good work!

grrnmo - July 17, 2010 at 9:57am

That is not relevant to a suggestion for a programmers approach to modifying the iOS...it is Apple legalspeak that has no place in these forums.

Sunil Issac - July 17, 2010 at 12:56pm

Yes,they have this solution,if you use pownage tool rather than redsnow ;to jailbreak,it will prevent upgrading baseband while you upgrade the firmware.So Choose your jailbreaking tool properly and the ipsw file need to be one provided from the link and not from stock apple firmware.... Hope this clarifies yur que.

RedruM - July 16, 2010 at 5:08pm

Look like my next phone will be errison or the black berry. Sick and tired with the apple

Nt02 - July 16, 2010 at 5:46pm

Why not android? About the same, if not better, than iOS.

Phucpholuc - July 16, 2010 at 5:58pm

@RedruM I can't agree with you more, there's just sooooo much bullshit about this strict control of the blob issue. This issue is JUST TOO MUCH. Can you believe this crap-- iPhone 4 allows baseband downgrade?!? Redrum, I want to know how you handled the blob before? was it as easier for you to get it down when the control wasn't as tight?

sh4508 - September 7, 2010 at 11:06pm

People without any Apple products shouldn't put any comments here.