Write TRS-80 Super Utility image to diskette?

DS diskette and my Mod 4 is not so equipped.) Steve, Are you sure you're not mistaken here? I'm positive that DMK image I sent you is single sided. Matthew Reed's TRSTools tells me the disk is DMK and the size is 180k, which would indicate a single sided double density 40 track disk? Also, my own machine has single sided drives and I'm sure this is the image I used to make a real disk. Thirdly, CopyCat is for single sided disks and this is what I used for the copying. I remember more clearly how I made a real SU4 disk now. I used that image I sent you, which as you would have noticed is not a self-booting disk, but rather contains SU4 as a file. I booted the Keil emulator with a CopyCat disk image I have. It's version 4.1 and says on the splash page it copies single sided diskettes (and I'm assuming only single-sided diskettes). I then linked the SU4 DMK image to drive 0 and put a real disk in drive 1 (which was mapped to a physical drive). Pressed enter and the disk was copied. I then could use this disk on the Model 4 by booting in a Model 4 DOS (e.g. TRSDOS 6.1), inserting the SU4 disk in drive 1 and calling up the file. My Model 4 is packed away so I just tried this procedure with Matthew Reed's TRS32 emulator. Although it created another SU4 disk image rather than a physical disk, everything worked as above. I'm wondering if your issues might be related to the Linux-based software. I'm not familiar with those TRS-80 emulators or tools at all. Cheers Terry (Tez) P.S. if anyone else following this wants to see/check the SU image I have in order to assist Steve with his puzzle it's here (for now) https://dl.dropboxusercontent.com/u/5399598/temp/SU4.dsk