Below are the steps for reloading DISCO-F746NG demo software.

Step 1: Get the Demo App; download STM32CubeF7 (Embedded software for STM32F7 series (HAL low level drivers, USB, TCP/IP, File system, RTOS, Graphic - coming with examples running on ST boards: Discovery kit and Evaluation boards)):

Browse to http://www.st.com/web/en/catalog/tools/PF261909

At the bottom of the page, below Sample & Buy, find STM32CubeF7 1.1.0 with a a red "Download" button on the right. Download the file "stm32cubef7.zip" and unzip it to some place where you remember to find it.

Step 2: Install the programming software (for windows); download STSW-LINK004 3.7.0 (STM32 ST-LINK utility):

Browse to http://www.st.com/web/en/catalog/tools/PF258168

At the bottom of the page, below Sample & Buy, find STSW-LINK004 3.7.0 with a a red "Download" button on the right. Download the file "stsw-link004.zip" and unzip "stsw-link004.zip"

Run "STM32 ST-LINK Utility_v3.7.0.exe" to install STM32 ST-Link Utility v3.7.0

Step 3: Program the demo software into your DISCO-F746NG

Start the STM32 ST-Link Utility

Select the required elf loader: Menu->External Loader Select N25Q128A_STM32F746G-DISCO

Load File: Menu->Open File... (CTRL+O) (Supported files *.bin *.hex)

Browse to the file "STM32Cube_FW_F7_V1.1.0\Projects\STM32746G-Discovery\Demonstration\Binaries\STM32746G-DISCO_Demo_V1.0.1.hex"

Program DISCO-F746NG: Menu->Target->Program and Verify... (CTRL+P)

Wait a minute or so until flashing the device finishes, and you should see the demo starting.