Greaseweazle – Flux level floppy disk tool

This page about the Greaseweazle is always being updated. Last update 7th April 2021

What is it?

The Greaseweazle USB devices allow flux level read AND write access to floppy disks. Software for the device is open source and is updated regularly. There is more information about the device on its GitHub wiki page : Greaseweazle Wiki

This is the main piece of hardware and software I used as part of my floppy disk recovery and transfer service.

My Greaseweazle devices


Greaseweazle Blue Pill Side View
“Blue Pill” version of the Greaseweazle F1 device

I purchased my F1 board direct from the designer, Keir. 2 boards were on offer, one with the standard 34 pin connector, and one with the 30 pin Amstrad type connector. I have only assembled the 34 pin version so far. The build was relatively easy, but you do need so solder some surface mounted resistors.

I programmed by STM32 device using a standard USB to TTL serial adapter. Alternatively, you can use a ST-Link programming adapter. There is more information about programming the devices here.

F7 Plus Rev 2

Greaseweazle F7 Plus Rev 2
Greaseweazle F7 Plus Rev 2

Purchased March 2021, the F7 Plus has a few additional features over the original F1 device I have. Extra features include

  • Jumperless Update
  • Multiple Drives – Allows simultaneous connection to two PC, or three Shugart, drives on a single ribbon cable. Useful for cased installations.
  • Write-Protect Jumper – Physically disables write capability, making it impossible to accidentally overwrite disks during preservation.
  • Buffered Outputs – Higher (40mA) output drive capability, needed for older floppy drives with strong input pull-ups (resistance <1kOhm).
  • 12v Power input – Allows board and drive to be powered from a single 12v power brick. These models are the only ones to directly support drives requiring a 12v supply; other models require such drives to be separately powered.
  • User Outputs – User-configurable outputs. Useful for non-standard control signals such as reduced write current (8″ drives).

What can they read?

Here is what I have done successfully with mine so far.

  • Written 5 1/4 disks for the Osborne 1 luggable computer
  • Written and read 3″ disks for use in the Amstrad CPC, the Amstrad PCW and the ZX Spectrum +3
  • Read and write 80 track 3″ disks as used on the Amstrad PCW 9512 (photo below)
  • Used the Amstrad DDI-1 external floppy drive. NOTE : If you plan to use yours with the Greaseweazle device, make sure you disconnect the 5v internally. Failure to do so may kill your Greaseweazle!
  • Written and read 5 1/4″ ADFS disks for the Acorn BBC computers
  • Written 3.5″ disks for the Commodore Amiga
3 inch drive and associated cales
Amstrad EME-232 80 track, double sided drive and associated cables

The software

The software for the greaseweazle devices is written in Python, so it is cross platform. I have been mainly using the software under Windows 10, but it can also be run on Mac OS and Linux. You can download the software from here : Greaseweazle Downloads

Other software

There is another really useful piece of software for Windows that makes it even easier to read and write your disks, especially if you are not a fan of using a command line interface. (I don’t mine the cli interface as I am a Linux guy)


This was the first piece of additional software I found. GreaseweazleGUI is a Windows GUI wrapper for the python script running Keir Fraser’s STM32F1/F7 “blue pill” microcontroller widget.

GreaseweazleGUI v2.66
GreaseweazleGUI v2.66

You can download GreaseweazleGUI from here: GreaseweazleGUI

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