Upon downloaded the firmware file, I opened the zip file and found three files inside:

YPK5.AUI

YPK5.ROM

YPK5.IMG

So how are we going to flash the new firmware to our Samsung YP-K5JAB mp3 player.

According to the website,

you can update the BIOS & Micom in yourself.

The usage is as follows :

Download the attached file

Run the attached file on the Windows, and the BIOS will be upgraded automatically

careful: - Never power off during the BIOS in updating.

Well, I do not think the above installation instruction is suitable for YP-K5JAB because there is no way you can flash a firmware by running a ZIP file.

So digging further into FAQ section of Samsung YP-K5JAP, finally I figure out the correct steps:

1. Connect to the USB port on your PC using the USB cable or adapter while holding the play button on the main body.
2. Press the Play button more than 5 seconds, the \"Player Recovery Device\" message is displayed on Device Manager.
3. Run the upgrade program.
4. When the program is running, the screen will show the progress.
5. The upgrade window will appear when the Recovery process is complete. Ensure that \"Quick Download\" is deselected. Click Start to begin the upgrade.
6. If you do not release Quick Download, you cannot proceed to upgrade. When the Quick Download is deselected, formatting will commence at the same time, and the saved file will be deleted.
7. When the upgrade is complete, reconnect the USB for the driver to be newly recognized.

Alternatively, you can try the Free Driver Scanner.