att sim card needed to unlock for t-mobile?

[achenn]

I have a 3GS currently unlocked/jailbroken (4.2.1 and 6.15) using redsn0w.
I'm trying to upgrade to 5.1.1. I found this tutorial to help- Upgrade jailbreak iPhone to iOS 5.1.1 preserve unlock baseband redsn0w

However, near the bottom of the page I noticed it said "Once ultrasn0w is installed the springboard will be restarted and the network will be found with the current inserted sim, as long as the baseband is unlockable or the sim is from the original carrier the network will be found" which made me think that an ATT sim card was needed before I could use my T-Mobile sim card. Can anyone clarify this? Can I go through the process 100% using only my T-Mobile sim card?

 

[Jmills87]

Jailbreaking bypasses the activation process so there is no need for an official SIM.

 

[ladasha]

Btw OP, there is a new way to downgarde baseband from 6.15.00

Sent from my iPhone 4S

 

[Thomasjtsi]

Btw OP, there is a new way to downgarde baseband from 6.15.00

http://www.iphoneforums.net/forum/iphone-unlocking-69/downgrading-3g-3gs-baseband-05-13-04-a-42452/

 

[ladasha]

http://www.iphoneforums.net/forum/iphone-unlocking-69/downgrading-3g-3gs-baseband-05-13-04-a-42452/

Thanks for givin the link

Sent from my iPhone 4S

 

[Thomasjtsi]

Thanks for givin the link

Welcome!!

 

[achenn]

Jailbreaking bypasses the activation process so there is no need for an official SIM.

thank you for answering- looks like i'll be upgrading my phone today

 

[achenn]

Btw OP, there is a new way to downgarde baseband from 6.15.00

Sent from my iPhone 4S

to my knowledge, 6.15 enabled me to use iPad apps. is there any reason i should downgrade to 5.13.04?

 

[ladasha]

to my knowledge, 6.15 enabled me to use iPad apps. is there any reason i should downgrade to 5.13.04?

It will enable gps again

Sent from my iPhone 4S

 

[achenn]

It will enable gps again

Sent from my iPhone 4S

odd, maybe this isn't what you mean by gps, but i've been using the maps app without issue and all of my location dependent apps work perfectly. am i missing something?

 

[ladasha]

odd, maybe this isn't what you mean by gps, but i've been using the maps app without issue and all of my location dependent apps work perfectly. am i missing something?

GPS is usually disabled when the iPad Baseband is installed. Just downgrade your baseband. It is still unlockable via ultrasn0w. Causes less problems

Sent from my iPhone 4S

 

[Jmills87]

1/10 users who upgrade to the iPad baseband don't lose GPS functionality, but no it does not allow you to use iPad apps, the only thing the 06.15.00 baseband does is allow you to unlock.