Upgrading a JailBroken iPhone 3G

[Sethide]

Hello,

I would like to update to my iPhone (MB500X) 3g to 4.0.1 (JailBroken through JailBreakMe.com)
-I have downloaded the file "iPhone1,2_4.0.1_8A306_Restore.ipsw"
-I have Itune 101.1.4 on my PC Windows XP Sp2
-I have Cydia and OpenSSH.
-I currently have 3.1.2 (7D11)
-I do NOT have a sim card inserted.

When I try to update it after few minutes I have an error 3194 from iTunes seding me to Update and restore alert messages on iPhone, iPad, and iPod touch

Please advice and help.
Thank you.
Regards,

[i.Annie]

1) You should take it up to 4.1 if anything. 4.2.1 even will do fine on an iPhone 3G. 4.0.1 is very bad for that device.

2) Check for SHSHs. You'll need 4.1 to go up to 4.1. If you don't have SHSHs, going to 4.2.1 is ok too.

3) You'll need to specify if you need to unlock (maintain the baseband) so that the proper jailbreak method can assessed.

[Sethide]

With Tiny Umbrella 4.21.02
I have this:
iPhone3G 4.0 (8A293)-3739509194028
iPhone3G 4.0.1 (8A306)-3739509194028
iPhone3G 4.0.2 (8A400)-3739509194028
iPhone3G 4.1 (8B117)-3739509194028
iPhone3G 4.2.1 (8C148)-3739509194028
iPhone3G 4.2b3 (8C5115c)-3739509194028

I don't need to unsimlock, it I think it already is before I JB it. It was probably already unlock or was never lock. It was bought in Australia, I was able to use a Spanish sim card in it.
I was told any thing up 3.1.3 will slowdown the iPhone 3g, is it true?

Thank you.

[i.Annie]

It will create a slight slowdown on 4.1 or 4.2.1 but if you disable multitasking and wallpaper it will be almost as good as 3.1.x.

If you're sure you don't need to preserve the baseband (to SIM unlock) then you can just hit upgrade to 4.2.1 in iTunes. Then jb it with Redsn0w 0.9.6b6. It looks like you have SHSHs so that's always good just in case anything goes wrong. But in this case since you don't need to unlock, you won't be using them.

[Sethide]

I also have iPhone1,2_3.1.2_7D11_Restore.ipsw
Would I be able to restore back to 3.1.2 without any problem and then reJB it if needed/wanted?
Thank you.

[i.Annie]

Yes if you'd like to stay on 3.1.2 you shouldn't have any errors restoring to it.

[Sethide]

Thank you i.Annie!

[i.Annie]

No problem