Question : How to disable multitasking on iOS4 iPhone 3G ?

I have an iPhone 3G and I have installed iOS 4 with jailbreak which of course enabled the multitasking...The problem is that 3G is too slow for multitasking and I cannot disable it without re-installing the firmware.
Is it possible to disable the multitasking without reflashing the firmware again?

Answer : How to disable multitasking on iOS4 iPhone 3G ?

I believe that you have to edit a .plist file after using SSH into the iPhone to access the filesystem.  By doing the following, we will edit a .plist and make it say that multitasking is not enabled.

1) - Install OpenSSH and AFC2Add from Cydia.

2) - Download WinSCP or iFunBox and learn how to SSH into your device (not hard at all, especially with iFunBox).  Your login name is root and your password is alpine (if you have not manually changed it).

3) SSH in and go to /System/Library/CoreServices/SpringBoard.app/ and look for N82AP.plist.

4) Look for Multitasking and it should say something like:

<value>Multitasking</value>
<key>True</key>

5) Change True to False then reboot your iPhone.

6) If you still can multitask, SSH back in and delete the value altogether.

7) If you did 6, reboot and try again.

This should fix the multitasking but leave wallpapers.  Make sure to backup the .plist before you do this to protect against unwanted damage or changes.