After almost 17 months of continuous, futile attempts, today I finally managed to write the "System Tools" boot floppy for Mac Plus, using the low-level rw board "Kryoflux".

Based on my experience, and seeing that it's rarely discussed online and that there aren't even remotely complete guides, I wanted to write this short guide so it can help others with their endeavors, without them having to go through what I went through.

That said, here's the guide:

What you'll need:

Kryoflux board (I used the Rosalie Rev E1)
USB A - USB B Cable (Also known as printer cable. The Kryoflux must be connected directly to your computer, otherwise you'll probably risk buffer and latency problems. Easier is better!)
IBM/PC floppy drive (I can't guarantee that all of them will work. I used a very common model, the Panasonic JU-256, and it works.)
Floppy cable (preferably the one with the little "horn" in the center of the plastic of the connector so you can be sure to attach it well)
External PSU for powering the floppy drive (ensure it has the berg connector). One from an older computer will work just fine. Remember, you'll need to jumper it to get it to start. Typically, just place a jumper between the green pin/cable and the black (ground) pin. Check your PSU's specifications, anyways.
Power cord for powering the PSU
3.5" (I used DD) floppies. New ones would be ideal. I've used older ones, and obviously some had bad sectors and didn't work completely, while others did. Therefore, if you're using older floppy disks, I recommend getting more than one.

Step 1: Find a valid image

Using Debian (Linux), use the file command to verify the image is valid:

bash

file SystemTools.img

You should get something like:

SystemTools.img: Macintosh HFS data (bootable) block size: 512, number of blocks: 1594

The key things to check: it must say HFS data, bootable, and the file must be exactly 819200 bytes.

On Windows there is no direct equivalent command. Just verify the file size in Explorer (right click --> Properties) or in PowerShell:

(Get-Item SystemTools.img).Length

The image should be exactly 819200 bytes (800k)

For verifying the filesystem type on Windows, you can use a tool like HxD hex editor and check that the file contains valid HFS data — but honestly, if the size is correct and the source is reliable, you can proceed.

The version I downloaded is an Italian one, but although it won't be useful to many, I'm attaching it anyway.

Step 2: Convert it into Kryoflux Stream files (.raw) using the "Macintosh.exe" commandline utility, perfected and shared by ZrX on this Kryoflux forum discussion (page 3).

I take this opportunity to thank you very much, ZrX!

Before converting, ensure you are in a specific directory, created for the raw files (the tool will create several files! )

# Linux 
mkdir systemtools
wine Macintosh.exe SystemTools.img systemtools/track 
# Windows
mkdir systemtools
Macintosh.exe SystemTools.img systemtools\track

If everything went well, the command should have returned no errors and you will see your new "systemtools" folder (or whatever you prefer to rename it) full of files named like track00.0.raw

Macintosh.exe may return errors stating that it doesn't support the format (this always happens to me with .dsk). To work around this, I recommend using "GreaseWeazle" to convert the image to formats like .img, which usually work.

For example (assuming you installed it with pip; otherwise, see the GreaseWeazle INSTALL manual file):

gw convert --format=mac.800 systemtools.dsk systemtools.img

Step 3: The Writing

And here we finally come to the most fun part (or the most hellish, depending on how you performed the previous steps).

For writing, as I mentioned previously, we'll use the "dtc" tool, which can be downloaded here from the official Kryoflux website, along with all the accompanying documentation.

If you're on Linux*, remember to use sudo before each dtc command.

If you're on Windows, launch the terminal as admin.

*If you're using Debian, you can download the official .deb package (contained) here to install dtc on your system.

Via terminal, navigate to the directory containing the binary file (the program file).

Make sure the PSU is properly powering the floppy drive and that the floppy drive is connected to the Kryoflux card, which in turn is connected directly to the computer you're using.

To initialize everything, run:

#Linux
sudo ./dtc -c2
#Windows
./dtc -c2

If you've done everything correctly, you'll see the kryoflux flash while the floppy drive emits increasingly long, "deep" sounds: good, kryoflux is mapping the drive.

Now comes the fun part. Insert the floppy disk into the drive (the hole is covered by the plastic switch!)

(if you are using an used, old floppy, consider "cleaning" it first with a magnet)

Make sure you're in the folder we created earlier containing all the raw files (e.g., track00.0.raw), and run:

# Linux
sudo ./dtc -w -f "track" -we2 -d0

# Windows
dtc -w -f "track" -we2 -d0

A quick aside: what does this command do? (Or, "What am I running?")

-w = write mode

-f "track" = write the series of files called "track"

-we2 = the real deal: write, but first electromagnetically erases the disk. For some users, this could not be enough. Try cleaning the floppy with neodymium or simple magnet before inserting.

-d0 = selects drive 0, which is the default (and technically useless) if you only have one drive connected.

Can you hear the floppy disk making noises? Good. Or maybe not. It depends. Let's check in the terminal what dtc is logging:

robic@robics-debian:~/floppy/appleSystem6ITa/systemtools-ita-raw$ sudo dtc -w -f"track" -we2 -d0

Image name: track
Image type: RAW
Image sides: 2
Image tracks: 80
Analysis time: 2.883 s
Side 0: td: 1, cf: off, data: 80, unformatted: 0, nfr: 0
Side 1: td: 1, cf: off, data: 80, unformatted: 0, nfr: 0
Filter mode: side -wg: 3, crosstalk -wk: 3
Side mode: side -g: 2, td -k: 2, flip -wy: 0, flippy -y: 0
Write mode: bias -wb: 0, erase -we: 2
83.0 : Wiping
83.1 : Wiping
82.0 : Wiping
82.1 : Wiping
[...]

If you see this, congratulations!

But wait...why all these errors?

Don't panic. All the floppies I've written have always given this output :

[...]
56.1 : The streaming device reported a transfer error
56.1 : Writing RAW
57.0 : Writing RAW
57.0 : The streaming device reported a transfer error
57.0 : Writing RAW
57.1 : Writing RAW
58.0 : Writing RAW
58.0 : The streaming device reported a transfer error
58.0 : Writing RAW
58.1 : Writing RAW
58.1 : The streaming device reported a transfer error
58.1 : Writing RAW
59.0 : Writing RAW
59.1 : Writing RAW
[...]

I don't have a definitive, scientific explanation for this. However, hypothetically, we can put it this way:

Remember that we're writing GCR images with an MFM drive: Kryoflux will therefore have to "play" with the floppy, making it move as an original Apple drive would.

In fact, it's possible to see that these errors aren't caused, for example, by floppy degradation (or at least not completely); in fact, every disk that returns an error immediately afterward actually reports a successful write, for example:

58.1: The streaming device reported a transfer error
58.1: Writing RAW

Wait for the floppy to finish each operation (making noises), and then you can eject your new floppy.

"Enjoy your new shiny Macintosh floppy"

Step 4: Done!

If everything went well, your floppy should be ready and working.

All that remains is to test it.

Now, Prometheus, you have fire in your hands. Use it wisely.

u/BlackTortellino

I created a (unofficial) .deb package for Ghidra; fully generated by Github Actions (CI/CD)

I created a wrapper for the simplest image to raw converter

Looking for working Balance of Power floppy image to write on floppy, for a real Mac Plus

Step 1: Find a valid image

Step 2: Convert it into Kryoflux Stream files (.raw) using the "Macintosh.exe" commandline utility, perfected and shared by ZrX on this Kryoflux forum discussion (page 3).

I take this opportunity to thank you very much, ZrX!

Step 3: The Writing

Step 4: Done!