How can I remove iOS 4.2 from an iPad?
Step 1: You need to put the iPad into recovery mode.

Press and hold the home and sleep/wake buttons until the device shuts off. Keep holding the home key until the "connect to iTunes" graphic appears on the screen.

Step 2: Make sure you have iOS 3.2 somewhere on your system. Drag it into the organizer. 

You can get any version of the iOS firmware from here.

Step 3: Open XCode's organizer and connect the iPad.

Step 4: Select your iPad in the organizer and choose the firmware version on the top right.



NOTE: You can probably use replace steps 3 and 4 with Option + Click in iTunes, just make sure to have the proper firmware lying around on your system.

NOTE2: Excuse me, I meant iOS 3.2, not iOS 4.1. I'm a little distracted at the moment.