Updating baseband on iphone 3gs?

I jailbroke my phone, and everything worked fine, now i'm trying to update the baseband so I can unlock the sim. Does anyone have a good site or know how to update the baseband? I'm at 05.16.05 right now and I need to be at 06.15.00.

Do you need to Unlock I-phone from Sim Lock (network lock) use Remote unlock service. It's best and easy method to unlock it… You can get the remote unlock service from the site http://www.prounlocking.com/apple-iphone-3g-s/rs8wp9/ and unlock it easily. You no need to update the baseband in this method… You no need to downgrade. You can just update the I-phone software to latest version and unlock it using the I-tunes.

  • Will updating my unlocked iPhone 3GS lock it again? My phone is on 4.1 and I wish to update it can I do so without it locking again? And if so can I do it on iTunes?
  • Will updating my iPhone apps affect my phone speed as how updating the Operating System (OS) will? Currently I'm using the iPhone 5s on iOS 8.3 I know if I were to update my phone to the latest OS I may notice some slowdown on my phone's performance, since it may not have the "muscle" to handle certain functions. Many apps now are optimised for iOS 9 and/or the 6th generation phones. Will my 5s' speed performance slow down if I update my apps? Will the app's performance slow down?
  • Will updating my iPhone 3GS delete everything on it I have an iPhone 3GS and I want to update it to the latest iOS so I can download the newer apps. When I try to download on it says it will delete all of my apps and media on my iPhone. Some people say it will restore it back after the update but why doesn't it say it anywhere on the message that pops up? Anyway I'm one click away from updating… Will it delete all my stuff?
  • Will updating my ios to 5.1.1 will also change the baseband? I have an iphone 3gs running on ios 4.3.5 with baseband 05.16.02 and I want to upgrade it to ios 5.1.1 but i'm afraid it might change my baseband. I'm NOT AN ULTRASNOW USER since it is not availble on 05.16.02 baseband.