Upgrade & jailbreak from 3.0 already jailbroken to 3.1.2 jailbroken

[Qanbar]

Hi guys have two 3gs' (mine & the wifes) one is release day model the other was bought in September last year. How can I check if the September model will be a tethered jailbreak?
On to my main question, my phone is 3.0 jailbroken I want to upgrade the software to 3.1.2 so I can install some apps that are 3.1 compatible. What's the procedure for me going to a 3.1.2 jb? Reason I ask is that apple have stopped signing the old software so not sure.
If/when I update to next fw jailbreak, how do I save any cracked or cydia apps (back them up) as well as my legit apps? I know about aptbackup is there another? How do they work?
finally if I can upgrade & jb are there connectivity issues as 3.0 is a dream.
Sorry for the mountain of qs, gotta a vague idea about the basics but just need some clear answers to put my mind at rest.

Thanks

 

[The General]

use pwnage to upgrade to 3.1.3 jailbreaked

 

[mreddys10]

Hi guys have two 3gs' (mine & the wifes) one is release day model the other was bought in September last year. How can I check if the September model will be a tethered jailbreak?
On to my main question, my phone is 3.0 jailbroken I want to upgrade the software to 3.1.2 so I can install some apps that are 3.1 compatible. What's the procedure for me going to a 3.1.2 jb? Reason I ask is that apple have stopped signing the old software so not sure.
If/when I update to next fw jailbreak, how do I save any cracked or cydia apps (back them up) as well as my legit apps? I know about aptbackup is there another? How do they work?
finally if I can upgrade & jb are there connectivity issues as 3.0 is a dream.
Sorry for the mountain of qs, gotta a vague idea about the basics but just need some clear answers to put my mind at rest.

Thanks

To find if you have a tethered or untethered jailbreak, go here: https://forums.macrumors.com/threads/814973/

If the iboot version is 359.3, then its a normal untethered JB. If its 359.3.2, its a tethered JB.

To upgrade an already JB'ed phone, create a custom firmware using pwnagetool. You can find instructions here: http://www.iclarified.com/entry/index.php?enid=5432

To backup cydia apps, aptbackup is good enough. It will store a list of what you have installed on cydia, and when you backup in iTunes, it will store that info in the backup files. Once you upgrade, and restore from a backup, u need to re-install aptbackup from cydia, and hit restore. This will then download all your previous cydia apps and reinstall them.

No connectivity issues. Pwnagetool will preserve your baseband, and you can still use ultrasn0w (very reliable).

 

[Qanbar]

Thanks mreddys10 answered everything I needed to know & more

 

[Qanbar]

im on Windows so used sn0wbreeze...loads up custom logo (after i create custom ipsw) but wont restore and i am stuck in DFU mode (image on iphone is usb with arrow pointing to itunes icon).
I have the latest version of Itunes is that the problem?
Help is needed as cant even make calls...lol

Update:
Everyone says not to use snowbreeze on here...saw a video by dinozambas on youtube and he is pretty reliable. Ok so what are my options i have my 3.0 ssh hashes stored with saurik (cydia) how do i go back to that 3.0 or get up t 3.1.3 jailbreak on windows.