B29 and the A-Bomb

How did the B29s avoid having their electronics, in particular their ignition systems, disabled from the emp resulting from the atomic bomb explosion?

jmb2fly, please explain what is "disabled from the emp"

Electro Magnetic Pulse. It is generated as a result of a nuclear explosion. I'm not sure but I suspect that the B29s would have been too close to the explosion to excape it's effects. It should have knocked out the ignition systems among other things. A friend of mine claims the Enola Gay was not the actual aircraft and crew that dropped the A-Bomb. He has an uncle who was a part of the unit that did drop the bomb and claims the aircraft that actually did the bombing were lost. I'm not so sure about that but it is an interesting question that I haven't heard most people ask.