Downgrade baseband with shsh? - GSM-Forum

https · 07-14-2010, 20:31

As a good user I have saved my shsh certificate file (since 3.1.3) for my 3GS (new bootrom). With that I can downgrade the firmware in the usual way. But with upgrading the firmware, we usually also upgrade the baseband. With the upgrade from 3.1.3 to 4.0 the baseband upgraded from 05.12.01 to 05.13.04.

When downgrading the firmware, the baseband does not downgrade. This happens since baseband 05.13.x.

Can someone explain more details? Can you confirm that the baseband now has the same upgrade mechanism with certificates by Apple like the firmware? If yes, is there a way to backup those certificates? Or are they included in the shsh file? Why is no downgrade possible? Because of missing downgrade software or because of missing certificate or because baseband never allows update to a lower version if it's working or what?

Can some insider explain this?

..::TheR3c0der::.. · 10-16-2010, 09:00

So if i have SHSH on Cydia from previous FW-s the baseband cant downgrade???

Burnt Cobba · 10-16-2010, 09:44

the only way via software is to try and use FUZZY BAND (check on cydia). It will work only on older bootrom as far as i used it last time.

The other way is to do it via hardware something which i would not suggest you do unless you are a Pro and know the ins and outs of how to do the procedure perfectly.

Check this thread for further details that our friend Galaxy*GSM opened:-

http://forum.gsmhosting.com/vbb/f456...ly-if-1117577/

..::TheR3c0der::.. · 10-16-2010, 12:37

Yes i know the hardware method but its dangerous and you must have a good hot air station or mostly an infrared station and universal programmer.

Someone knows about something like TP method? I heard something but maybe its for the old 2g solution by geohot.

https · 10-17-2010, 15:58

What is the TP method?

I thought the hardware method only worked on old phones? I'm not aware that the Infineon XMM 6180 (baseband processor of iPhone 4) can be reprogrammed. Let me know if you know it can be done and how (what hardware etc.).

07-14-2010, 20:31	#1 (permalink)
https No Life Poster Join Date: Mar 2010 Posts: 1,211 Member: 1263932 Status: Offline Thanks Meter: 181	Downgrade baseband with shsh? As a good user I have saved my shsh certificate file (since 3.1.3) for my 3GS (new bootrom). With that I can downgrade the firmware in the usual way. But with upgrading the firmware, we usually also upgrade the baseband. With the upgrade from 3.1.3 to 4.0 the baseband upgraded from 05.12.01 to 05.13.04. When downgrading the firmware, the baseband does not downgrade. This happens since baseband 05.13.x. Can someone explain more details? Can you confirm that the baseband now has the same upgrade mechanism with certificates by Apple like the firmware? If yes, is there a way to backup those certificates? Or are they included in the shsh file? Why is no downgrade possible? Because of missing downgrade software or because of missing certificate or because baseband never allows update to a lower version if it's working or what? Can some insider explain this?

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10-16-2010, 09:00	#2 (permalink)
..::TheR3c0der::.. Major Poster Join Date: Oct 2010 Location: Under the Bridge Age: 36 Posts: 48 Member: 1409331 Status: Offline Thanks Meter: 39	So if i have SHSH on Cydia from previous FW-s the baseband cant downgrade???

10-16-2010, 09:44	#3 (permalink)
Burnt Cobba No Life Poster Join Date: Apr 2002 Location: The Green Mile Posts: 3,653 Member: 11325 Status: Offline Thanks Meter: 266	the only way via software is to try and use FUZZY BAND (check on cydia). It will work only on older bootrom as far as i used it last time. The other way is to do it via hardware something which i would not suggest you do unless you are a Pro and know the ins and outs of how to do the procedure perfectly. Check this thread for further details that our friend Galaxy*GSM opened:- http://forum.gsmhosting.com/vbb/f456...ly-if-1117577/

10-16-2010, 12:37	#4 (permalink)
..::TheR3c0der::.. Major Poster Join Date: Oct 2010 Location: Under the Bridge Age: 36 Posts: 48 Member: 1409331 Status: Offline Thanks Meter: 39	Yes i know the hardware method but its dangerous and you must have a good hot air station or mostly an infrared station and universal programmer. Someone knows about something like TP method? I heard something but maybe its for the old 2g solution by geohot.

10-17-2010, 15:58	#5 (permalink)
https No Life Poster Join Date: Mar 2010 Posts: 1,211 Member: 1263932 Status: Offline Thanks Meter: 181	What is the TP method? I thought the hardware method only worked on old phones? I'm not aware that the Infineon XMM 6180 (baseband processor of iPhone 4) can be reprogrammed. Let me know if you know it can be done and how (what hardware etc.).