JB versions vs fw versions: must they match?

[douglh]

Short description: is PwnageTool 3.1.2 only good for firmware 3.1.2, and nothing else?

Longer: My 3g is running 4.2.1 and the battery life sucks. To downgrade to 3.1.2 do I use PwnageTool 3.1.2 (what I want to go to) or do I use PwnageTool 4.2.1? Do I want the Tool to match where I'm going or where I'm coming from? Or does t matter at all?

I assume this has to do with the patch that Pwnage applies.

[reddawg]

Short description: is PwnageTool 3.1.2 only good for firmware 3.1.2, and nothing else?

Longer: My 3g is running 4.2.1 and the battery life sucks. To downgrade to 3.1.2 do I use PwnageTool 3.1.2 (what I want to go to) or do I use PwnageTool 4.2.1? Do I want the Tool to match where I'm going or where I'm coming from? Or does t matter at all?

I assume this has to do with the patch that Pwnage applies.

Yes, 3.1.2 was the best firmware for battery life. That being said, many people cripple their battery life after jailbreaking by restoring from backup in iTunes. Here are a few things to consider before jumping back to iOS 3.1.2.

1. After restoring your custom firmware, did you select "Setup as a new phone" or "restore from backup" in iTunes. Always set up your iPhone as a "new phone". Restoring from backup is known to cause severe battery issues.
   
2. Don't hacktivate your custom firmware. When creating your custom firmware in PwnageTool, do not select "Activate the phone". After restoring your custom firmware, activate your iPhone 3G in iTunes using an official carrier SIM card. If you do not have an official carrier SIM card, then borrow a friend's SIM card to do this. This will fix "Push Notifications" and help improve your battery life a little.

If you are going to downgrade your iPhone 3G's firmware from 4.x to 3.1.2, you will need PwnageTool 3.1.4. You may need to downgrade your iTunes to version 9.0.1 as well. Make sure you put your iPhone 3G into DFU mode before restoring the custom firmware.

[douglh]

Yes, 3.1.2 was the best firmware for battery life. That being said, many people cripple their battery life after jailbreaking by restoring from backup in iTunes. Here are a few things to consider before jumping back to iOS 3.1.2.

1. After restoring your custom firmware, did you select "Setup as a new phone" or "restore from backup" in iTunes. Always set up your iPhone as a "new phone". Restoring from backup is known to cause severe battery issues.
   
2. Don't hacktivate your custom firmware. When creating your custom firmware in PwnageTool, do not select "Activate the phone". After restoring your custom firmware, activate your iPhone 3G in iTunes using an official carrier SIM card. If you do not have an official carrier SIM card, then borrow a friend's SIM card to do this. This will fix "Push Notifications" and help improve your battery life a little.

If you are going to downgrade your iPhone 3G's firmware from 4.x to 3.1.2, you will need PwnageTool 3.1.4. You may need to downgrade your iTunes to version 9.0.1 as well. Make sure you put your iPhone 3G into DFU mode before restoring the custom firmware.

Thank you for all that. Because nobody answered until your post, I was going to update the post saying I still wanted to know all that but it became less urgent a few hours before your reply.

I read that an unlocked iPhone with a non-stock SIM card will function but will constantly be sending out signals looking for the correct Carrier. I installed SAM and SAMprefs and ran them. I may not have the details right but I gather what it does in de-activate the iPhone, remove all traces or references to the correct Carrier, make the iPhone believe that the installed SIM is the original one. then have iTunes activate it as if it was the original Carrier.

The process took less than half an hour, it was free, and battery drain is significantly reduced.

So thanks for answering my questions and I hope this helps anyone else.