iceflashprog

Host software

The iceflashprog command-line tool communicates with the iceflashprog device over USB HID to read, write, erase, and verify flash memory on iCE40 FPGA development boards. It is written in Go and uses the usbhid library for cross-platform USB HID access.

Installation

Prebuilt binaries

Prebuilt binaries are available from the latest release (v0.1.0):

The Linux archives also include the udev rules file.

Building from source

A Go compiler 1.24 or later is required:

go install rafaelmartins.com/p/iceflashprog@latest

Or from a local clone:

go build -o iceflashprog

Linux udev rules

Linux users need to install a udev rules file to allow non-root access to the device. The rules file is included with the prebuilt binary archives.

To install manually:

sudo cp 60-iceflashprog.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules
sudo udevadm trigger

The rule grants access to members of the plugdev group and to locally logged-in users (via uaccess).

Usage

Detect flash memory

Verify that the device is connected and the flash memory is accessible:

iceflashprog -d

Expected output:

Manufacturer: 0x1c
Device ID: 0x7015

The manufacturer ID and device ID values depend on the specific flash chip on the FPGA board.

Write bitstream to flash

Write a bitstream binary file to the flash memory. This erases the affected 64 KB blocks before writing and the firmware verifies each 256-byte page after writing:

iceflashprog bitstream.bin

To skip the erase step (useful if the flash was already erased):

iceflashprog -n bitstream.bin

Verify flash contents

Compare a local file against the contents of the flash memory:

iceflashprog -c bitstream.bin

Read flash memory to file

Read the entire flash memory (2 MB) to a local file:

iceflashprog -r output.bin

Erase entire flash

Erase the entire flash chip:

iceflashprog -e

Multiple devices

When multiple iceflashprog devices are connected, select a specific device by its serial number:

iceflashprog -s "SERIAL_NUMBER" bitstream.bin

If multiple devices are detected and no serial number is provided, the tool reports the available serial numbers as an error.

Show version

iceflashprog -V

Command-line reference