Upgrade iPhone 3G from OS 3.1.3 to 4.2.1

[IMGR8EST]

I have a jailbroken & unlocked iPhone 3G with OS 3.1.3 and baseband 05.12.01.

Can it be upgraded to OS 4.1.2 and if so request to kindly detail the steps.

Thank You

[i.Annie]

I'd recommend staying on 3.1.3 for best performance.

But if you insist, you can do so with SHSHs. Check to see if you have 4.2.1 SHSHs first with TinyUmbrella from thefirmwareumbrella.blogspot.com. Click Save SHSH and see what the log says about having 4.2.1 saved.

[IMGR8EST]

I would want to continue on OS 3.1.3. The only reason, I see now is the ability to have alerts on the main screen which do come with built-in Calendar App but are erratic (sometimes do not appear). Is there an application that works on 3.1.3 and gives alerts and notifications on the main screen without syncing?

[Goof]

If your really want to update then I would try whited00r

[sieutoc]

I'd recommend staying on 3.1.3 for best performance.

But if you insist, you can do so with SHSHs. Check to see if you have 4.2.1 SHSHs first with TinyUmbrella from thefirmwareumbrella.blogspot.com. Click Save SHSH and see what the log says about having 4.2.1 saved.

What do I do if I have my shsh save for 4.1 and 4.2.1. Does it mean if I upgrade to 4.2.1 and I can downgrade to 4.1 if I want?Not sure how the shsh blob work.

[i.Annie]

Having SHSHs for 4.1 and 4.2.1 means you can restore to those whenever you want/need to

You would just run TinyUmbrella's TSS Server and restore to the firmware you want that you have SHSHs for.

[sieutoc]

Ah thanks. Another thing which iOS 4.x you recommend for 3G? I really want some of the apps in 4.x their useful and good. I only have shsh for 4.1 & 4.2.1.

[i.Annie]

I don't recommend any iOS 4 for iPhone 3G lol. No but yeah, 4.1 or 4.2.1 is much better than 4.0.x. So long as you disable multitasking and wallpaper on them.

[sieutoc]

Ok thanks. How slow is it at 4.x? Is it still usable? Are games able to be play on without lag or pause? Which jailbreak method you recommend?

[i.Annie]

It should run pretty well with multitasking and wallpaper disabled. If those are not disabled, you might get frustrated at the lag or freezes.

Games might skip too. But like I said if you disable multitask and wallpaper, it should be ok.

If you find you don't like it at all, you can always downgrade back to 3.1.3 without SHSHs on iPhone 3G.

If you need to maintain your unlock, your jb methods are limited to using custom firmwares. Sn0wbreeze for PC and PwnageTool for Mac. These work for both 4.1 and 4.2.1, given you use the right version per firmware.

[sieutoc]

How successful has snowbreeze been working to preserve baseband? Also, how do I restore back to 3.1.2 if no shsh save? Do I just restore it through iTunes with apple 3.1.2 firmware? Please give more insight or link. Thanks