HP LaserJet P3015 - Macro Thumb Drive Format

[SearsJ]

The company I work for has an HP LaserJet P3015 printer that they use to print checks.  At some point, I think a third party company, possibly Meier Business Systems out of Texas (which I believe is now defunct), set up some kind of thumb drive with macros on it that the printer appears to use to load the format for the checks.  

From the printer configuration, I can pull up a directory listing of the files on the drive, but If I take the thumb drive and plug it into my Windows 10 PC, it tells the drive would have to be formatted to do anything with it and won't read it.

Can anybody tell me what file format this thumb drive might be in so that I can find a way to view and possibly edit the files?

Thanks,

Josh

[Repairatrooper]

Often the check fonts and related info are encoded and not readily readable. This is done because there is often sensitive data like electronic signatures stored on them.

[SearsJ]

Oh, for sure.  I don't want to mess with the fonts but I think this usb drive loads logos and and probably the overall template format of the checks and I'm trying to figure out how it works so that we can try to replicate it on a newer printer like a Troy-branded HP M607. 

The LaserJet P3015 was recently dropped and still works, but it has put us in a weird situation where we realized that we don't really know how it prints checks.  If we try to print checks to the same model printer without the thumb drive in it, you just get a few lines of text.  There are no logos or columns or anything.

Currently, if I plug the thumb drive into an M607, it says, "Attached thumb drive is not formatted for use with this device".  It works perfectly fine with P3015s, so whatever file system was used for this thumb drive, the P3015 will read it, but a newer printer will not.  Windows 10 also doesn't recognize the file system.  This thumb drive may be from 1997, but even if it's in FAT 16 format, I would think Windows 10 would recognize it.  Ubuntu Linux doesn't recognize it.

Here's a picture of what the first file directory page looks like if that helps anyone explain what this is and what file format it might be in.