Does anyone remember how to hack iPod Nano (4th gen) firmware images?

[thejadedmonkey]

I recall a while ago, there was a way to download the iPod firmware and hack it to support all sorts of things. I gave my 3G iPod hebrew with a hacked Firmware update that supported Hebrew, and I was able to open the file in a resource editor to change the "snycing" and "charging" images.

Does anyone know how do accomplish this on the 4th gen nano, or if it's even still possible?