Thanks for the info! I'm well-versed with the limitations of hex-editing binaries... way back in the 'old days' I was customizing the 'os' on my Tandy 102 portable.
I went through the ccpmp.bin file, that seems to be the main file for the whole system. I was able to locate the Native Apps mountpoint in there. The mountpoints are plain text ending with a null, and there were another three nulls before the next bit of text. So I changed it from "a:\game\" to "a:\game\10\" then set up my games subfolders with two-digit names.
I just have to figure out where the mountpoint for 'Interesting Games' is... I don't want to change all the a:\games\ references as I want to leave all the .sim, .cfg, etc files in there. (It was easy to find the native apps one as it had "*.app|*.dir" next to it.)
Edited to add: Also while I was mucking around in there, I noticed that there is a codec for AAC (m4a) audio files. And in the /system/res/filetypes directory there is an icon for m4a, but when I put m4a files into my music directory, they did not show up. When I went into the file browser, the files were there but with the 'unknown file' icon. So while I was editing the mountpoint, I went to the music one where it had all the music file types, i.e. a:\music and "*.mp3|*.ra| et cetera" and I changed the *.ape to *.m4a. Now my m4a files show up in the music player and they play fine, though they still have the 'unknown file' icon.
I'm going to try changing other ape references to m4a to see if I can fix the icon thing.
Has anyone else had problems with .m4a audio files? I'm just wondering why they'd have an AAC codec in there but not have the m4a files show up in the player...
Edited again: Success!
The Native Apps mountpoint is in ccpmp.bin at offset 0x175784
The Interesting Games mountpoint is in ccpmp.bin at offset 0x1759AC
(This is from a 1.2 a320.hxf file - the offsets may be different in other versions)
In both cases there is enough room to add two more characters plus the trailing backslash.
For the AAC / m4a I just did a search for the "ape"... there were about a half dozen references that I changed to "m4a". I did not change all of them - only the ones where "ape" appeared along with a list of other music file suffixes. After having done this, the Dingoo recognizes all AAC / *.m4a audio files, catalogues them and they appear correctly in the music player.