Iphone 3G looking to upgrade need help please!

[Lebowske]

I have an 8GIG iPhone 3G running on 3.1.2 I believe with a Modem firmware of 05.11.07 and notice would like up upgrade to just under 4.0 because my phone has gotten a little glitchy and I believe that an upgrade would help it out. I am on T-Mobile and would like to know if there is anyway I can update without loosing all of my Mods I have done and still keep it on T-Mobile.

[iYeow]

Since your iphone is glitchy, you will need restore not update, update will simply transfer your glitchy stuff to the new firmware.
Yes, you will lose all your mod, you need a restore and rejailbreak again. That is the price you have to pay if you want to keep your iphone jailbroken.

[Lebowske]

wont restoring automatically update me to the newest firmware whether i like it or not?

[iYeow]

Yes it will, unless you do a shift + restore or option + restore, then you can choose your firmware