USB key not readable by a certain device when formatted using fdisk

Question

My mother has a radio that can play MP3s on a USB key. I noticed something strange. When I format it with diskpart from Windows 8.1 my mother's radio has no problems playing the MP3s on a USB key, but if I do the same with fdisk, the radio just says that there are no files on the USB key.

So, this is what I did to make sure, I was not just imagining things:

1. First, I did a quick delete of all the files in the USB key with:

   sudo dd if=/dev/zero of=/dev/sdb bs=4M count=1

   Well, that deletes the MBR, partition table thoroughly. (I know I do not need to delete 4M to delete everything, but I was not sure about gpt and stuff.)

2. I formatted the USB key with Windows diskpart

   diskpart
   list disk
   select disk 1
   clean
   create partition primary
   select partition 1
   active
   format fs=fat32 quick
   exit

   It works perfectly on my mother's radio!

3. Now I format it with fdisk after deleting everything like above with dd:

   sudo fdisk /dev/sdb
   n
   p
   (return 3x)
   a
   w
   sudo mkfs.vfat -F 32 /dev/sdb1
   

   Now for some reason it doesn't work!

Here is the information gparted gives me when I format the USB key with fdisk:

And here is the information when formatted with diskpart:

Please tell me if there is a way to make the USB key work on my mother's radio without having to boot up Windows all the time. Thanks!

Answer 1

You didn't set the partition type in fdisk. Most modern operating systems (including Linux itself) ignore it anyway and just look at the file system. But certain embedded devices don't recognize the file system if the partition type isn't set properly.

While partitioning your USB device, type tin fdisk and set the partition type to c (W95 FAT32 LBA).