ImgBurn automatically booktypes +R media to DVD-ROM on Samsung burners, so you don't need to worry about it. Also, you do know that the booktype is only written to the disc when you actually burn it, right?
By the way, you can find the latest firmware for your burner here (remove any disc and close the tray before updating then reboot after it's finished). And while you're at it, also have a look here