iphone 3g format and rejailbreak?

[Rochenel]

hi guys im new to iphones so my iphone is jailbroken by redsn0w
and i want to format it and rejailbreak again coz after i jailbreak
it suddenly getting lag and i install cydia apps like winterboard
and gpSPhone but when i open it its only blackscreen after
5sec it will crash idk why ive install the cydia and cydia apps by
diskaid deb files, so please help me with this guys step by step
help me please i will appreciate it

iphone 3g
version : 4.2.1 (8C148)
carrier : Carrier 9.0
Model : MB489J
Modem Firmware : 06.15.00 (im not sure about this coz "I THINK" before i jailbreak it, it was 5.15 but im not sure)

please guide me step by step and suggestions will be very appreciated.
THANKS!!!

by the way im new to iphone so i dnt knw alot about it like SHSH or something like that XD

 

[Applejuiced]

You will need to research, learn and educate yourself before you try anything.
What you need to do is create a custom 4.2.1 ipsw with redsnow.
Restore to that and then you can use redsnow again to downgrade your baseband from the ipad bb to an older unlockable version.
Assuming you're using it unlocked on unofficial carrier you will then need to install ultrasnow from cydia to unlock.
There's many steps you need to go through and other little things so do some searching and ask any specific questions if you have any.
Dont expect anyone to hold your hand step by step.

 

[Rochenel]

You will need to research, learn and educate yourself before you try anything.
What you need to do is create a custom 4.2.1 ipsw with redsnow.
Restore to that and then you can use redsnow again to downgrade your baseband from the ipad bb to an older unlockable version.
Assuming you're using it unlocked on unofficial carrier you will then need to install ultrasnow from cydia to unlock.
There's many steps you need to go through and other little things so do some searching and ask any specific questions if you have any.
Dont expect anyone to hold your hand step by step.

hello, yep i did some research and i did install ultranow after i jailbreak it but its kinda really confusing but ill try my best thou so can u please tell me what should i do?

 

[Applejuiced]

Where are you stuck?
What firmware and bb are you on now?
Did you try downgrading your basebaband with the latest redsnow?