I can confirm the below as I tried USB podcasting with a great USB MXL voice mic. iOS 3.2 worked flawlessly, but iOS 4.2 requires external power. If battery life of the iPad had been improved, this would have been a so-so move and one that many may have been able to have stomached.

But, battery life doesn't seem to have gotten better. Rather, it seems worse to me. Coupled to a number of devices that no longer work without external power, it is a BIG bugger.

The following comes from TC Geeks.

If you have upgraded to iOS 4.2 recently and then tried to use the Apple Camera Connect Kit with other devices that used to work on 3.2, you might be a bit dismayed. Originally brought up in the the Apple support forums and then reported on over at TUAW, users are finding that iOS 4.2 is preventing several USB devices from working via the Camera Connection Kit.

There were some changes introduced in IOS 4.2 which have apparently caused the Apple Camera Connection Kit to become less useful for iPad owners that enjoyed using it with other USB devices. Essentially, as of the iOS 4.2 update, the amount of electricity the iPad’s 30-pin dock connector can put out has been slashed from 100mA to 20mA. Was this done to help with battery life? Because if it was, according this article we wrote there are definitely more issues that this with iOS 4.2 causing the iPad’s battery to drain faster than the previous iOS.

So basically, this means bad news for anyone trying to connect nearly any unpowered USB device to the iPad via the connection kit. This includes the following:

USB Keyboards
Flash Drives
USB Microphones
When you try to connect one of these devices you will get the following error, “The connected USB device requires too much power.”

Cameras should still work just as they normally do since they are all (mostly) self powered. While this is what the Camera Connection Kit was originally intended for anyway, most people won’t be dismayed but for those that found it convenient to be able to add other devices this will be frustrating.

What is interesting is that over on our iPad 2 information and resources page, we have a story related to the next generation of iPad supposedly getting a USB port. Perhaps this was done on purpose or perhaps it’s just a bug?