Since you are a linux user I don’t think you’ll be too shy to use the method I used to use with another nonSansa MP3 player I used that also played files in the order they were copied. I used a command prompt procedure to make a batch file and run it to do the copying in order.
On the windows machine, I’d open a command window and CD to the directory where the MP3 files lived. Then I would do the command:
DIR *.mp3 /B > TEMP.BAT
Which would create a text file with the bare MP3 file names, one per line.
Then open TEMP.BAT in a text editor, and put a "COPY " at the front of each line, and append the drive letter where the MP3 player is mounted to the end of each line. so you end up with a file with lines like
COPY spaceprison_01_godwin_64kb.mp3 F:
COPY spaceprison_02_godwin_64kb.mp3 F:
COPY spaceprison_03_godwin_64kb.mp3 F:
COPY spaceprison_04_godwin_64kb.mp3 F:
You can also use the text editor to fix problems like the fact that CHAPTER11.mp3 comes in alphabetical order before CHAPTER2.mp3.
Sometime it is useful to reformat the MP3 player to get a virgin FAT filesystem directory, or at leadt MKDIR a new directory and CD to it on the drive letter of the MP3. That way there is not residual junk in the filesystem directory.
