Downloaded the firmware update and copied onto both a USB drive and an SD card.  Tried to update my NEX 4000, first with USB, then with SD.  Both times, I get an error message that says it has "trouble reading, make sure update files are on root level and try again."  The files are the only files on either device.  Suggestions?  Am I doing something wrong?

Did you copy only the folder that says AVICNEX5000?

I dragged that exact folder to both types of media. I'm on a Mac; does the format of the media matter?

I think an SD card has to be formatted as FAT to work.

You will also need to get all the hidden files that Macs put on storage media off.  There's a free utility called Clean My Drive on the Mac App Store that will automatically do this when you eject any external drive or media.

Reformatted the SD card at FAT and it worked; thanks for the help!

Glad it worked!

I tried to format my sd card as fat but its a 16gig micro sd card and it does not support that high of a card..when formatted as ntfs the radio gives me the same error message as well as formatted as fat32..any suggestions anyone I am unable to update..thanks in advance

Couple of things to try. I was able to get the update working after having similar issues. First don't use a Sandisk Thumb drive and second empty the trash on your computer before you eject the thumb drive. Goodluck.