May 13, 2004 How to upgrade Iphone 3GS 4.2.1 (BB 05.13.04) Using custom firmware.(Guide) Because once you upgrade your baseband to 6.15.00 you cannot update your phone with apple original firmware in future. Before you Start this procedure. ✓ iOS 4.2.1 (8C148) 18th November 2010 339 MB: iPhone1,24.2.18C148Restore.ipsw ✓ iOS 4.1 (8B117).

Custom Firmware iOS 4.2.1 iPHONE 3G release today!

I can succesfully confirm i was able to build a fully working iOS 4.2.1 Custom firmware, that allows you to restore your iPhone 3G iOS 4.2.1 Baseband 06.15.00 without any problems.

I also managed to fix the battery issue problem, which is caused to Baseband update 06.15.00!

After testing for any bugs i will upload and release the Custom Firmware 4.2.1 for iPhone 3G in the night from 1st to 2nd Decembre on this blog.

For iPhone 3Gs pls stay tuned! I am working on it!

1. Hey man I’m looking forward into it!!!
   Need it much.
   Thanks 🙂

   December 2, 2010 at 7:04 am
   

2. Also will your custom firmware ask for activation or I will be hacktivated as default?
   Actually I heard that I can fix battery problem by activating my iphone with the oficcial sim (I have one), I want to try that and I was looking for a solution to restore my already “hacked” iphone 3G with 4.2.1 ios and 6.15.00 baseband because I need it to be NON-ACTIVATED nor hacktivated but ultrasn0w automatically makes it hacktivated.
   Please kindly comment.

   December 2, 2010 at 7:12 am
   

3. I’m on 3.1.3 ios and 6.15.00 baseband right now!!! Your video is great. Thank you much.
   I want you to upgrade your video a bit because it might not be understandable to some newbies (i’m not registered on youtube so i write it here):

   1) Description says “How to downgrade iPhone 3G iOS 4.1.2 to 3.1.3 without SHSH and BATT ISSUE FIX”
   i think you misstyped with 4.1.2. Change it to 4.2.1. It might confuse some people.

   2) Step 6 says “unplug usd cable from your computer not phone” I think you should add to step 6 “then plug it to computer again”

   3) Between step 2 and step 3 I think there should be step 2.5 that says “after you started iREB process iTunes will open automatically you need to close it till the iREB finishes its work”

   Regards!!

   December 2, 2010 at 9:59 am
   

4. I have a 3G with 4.1 and baseband 6.15. Should I upgrade to 4.2.1 official firmware before applying this custom firmware?

   I haven’t tried, but I have a feeling the official Apple firmware won’t work on my phone due to the baseband conflict.

   Any tips for me? Thanks

   December 2, 2010 at 12:37 pm
   

5. please bro help me out… im from venzuela… i had my iphone 3g on 4.2.1 os baseband 6.15 working yesterday… it was really slow, then i tried to do a recovery and star my iphone like a new phone… but itunes dont leave me to do it… is stock on, i think, restore mode (thats what itunes said) always show me the 1050 error… and on my iphone screen just keep showing the *connect to itunes message*… i dont know what to do now… is my iphone broke? im so dessperate and on madness edge

   December 6, 2010 at 1:39 am
   

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