3G downgrade help 4.2.1 w/ BB 06.15 to 3.1.3

[carlo_p0gi]

How do I downgrade my iPhone 3G (jailbroken, BB 06.15.00, unlocked via ultrasn0w 1.1-2), to 3.1.3 jailbroken?

[iYeow]

Put your iphone into dfu mode and run itunes : shift + restore to 3.1.3.
Use Exit recovery to kick out error 1015 from Tiny Umbrella

[carlo_p0gi]

would it still have the 06.15.00 baseband and unlocked by ultrasn0w?
what I meant was how would i downgrade it without changing the basebanf 06.15.00

[MiStO]

no it would not change ur baseband u will end up having 1015 error on itunes if u restore official firmware if u restore custom firmware its restore all fine.
but 0.6.15.00 ipad baseband Remains there in both cases n u can unlock ur iphone using ultrasnow 1.2
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[carlo_p0gi]

yeah i just did that.
the problem now is i'm unsatisfied with 3.1.3.
I jsut went to 4.2.1 but im stuck in recovery loop, cant's get it out even if i use tiny umbrella.

I figured i would need the custom IPSW for 4.2.1, is this correct?

[gauravsuneja]

yup

[Psyko]

If you use sn0wbreeze to build a custom IPSW it wont update your baseband, which means iTunes wont try to, and it wont error out. As a perk you have the IPSW install i.e. ultrasn0w and cydia for you, so when you have installed the firmware, you're already unlocked, jailbroken and activated

[douglh]

I'm a little slow today, lets go thru this slowly. Using the second post in this thread:
Put iPhone into DFU - ok.
Run iTunes, and Shift + restore, - and select the 3.1.3 file?
Then error 1015 comes from itunes?
Then I quit iTunes and start TinyUmbrella or leave iTunes running AND start TinyUmbrella?

[JohnnyPrimus]

Then I quit iTunes and start TinyUmbrella or leave iTunes running AND start TinyUmbrella?

either will work fine.

[Psyko]

Well, since iTunes automatically will try to install the 3.1.3 baseband (but fail since you have a newer one) there is a chance that TinyUmbrella wont help you.

Your best bet is to use PwnedDFU for the phone to accept custom IPSW's, then build a custom IPSW for your desired firmware and restore to this. The phone will be automatically activated, and if you so wish: Jailbroken and unlocked.

[JohnnyPrimus]

Well, since iTunes automatically will try to install the 3.1.3 baseband (but fail since you have a newer one) there is a chance that TinyUmbrella wont help you.

Your best bet is to use PwnedDFU for the phone to accept custom IPSW's, then build a custom IPSW for your desired firmware and restore to this. The phone will be automatically activated, and if you so wish: Jailbroken and unlocked.

When downgrading from 4.x w/ 6.15.00 iTunes will throw a 1015 error but TinyUmbrella will kick it out of recovery mode. 3.1.3 does not require SHSH blobs and the restore will not fail because of the baseband. This is only true when downgrading to 3.1.3 specifically.

[smalss]

Do you still need to put the iPhone into DFU before you shift restore if you have created a custom 3.1.3 firmware with snowbreeze or pwnage?

[JohnnyPrimus]

You can revert to the unmodified 3.1.3 ipsw even if you have 6.15.00 baseband.