The "Install STM32Cube Firmware" may fail because STM32Cube is trying to install a software update, but fails because of a connection issue. In restrictive IT environments, there might be no way to allow updates to be downloaded and installed.
To install the firmware manually, please do the following:
1. As a preparatory step, open STM32Cube software and attempt to create a project and generate code from it. This ensures that the software functions correctly, even without the latest update.
2. Open MATLAB and enter the following command in the MATLAB command window:
>> struct2table(jsondecode(fileread(fullfile(stm32cube.utils.getSharedRootDir,'stm32mcuinfo.json'))))
3. Look for your STM32 series listed in the "name" column and note the tested firmware version specified in the "version" column. For example, the supported firmware version for F4xx-based MCUs is 1.26.2.:
{'STM32F4xx Based MCUs'} {'stm32cube_f4'} {'STM32Cube_FW_F4'} {'F4'} {'1.26.2'}
4. Open STM32CubeMX software. Navigate to Help > Manage embedded software packages. Download the firmware for your required series as supported by MATLAB: 
5. Navigate to Help > Updater Settings to find the Repository Folder path.
6. Return to MATLAB. Enter the following command in the MATLAB Prompt:where <pathToRepositoryFolder> should be the directory obtained in step 5.
>> setpref('MW_STM32','STM32CubeFW','<pathToRepositoryFolder>')
7. Navigate to Add-Ons > Manage Add-Ons, and launch the setup for the STM32 Support Package.
8. When you get to the "Select STM32Cube Firmware Repository" step, the path specified in step 6 should already be shown in the edit field:
8. Press Cancel. Since the Firmware Repository folder has already been specified in step 6 and contains all the required Firmware versions needed by the support package, there is no more need to finish the remaining setup steps.
By following these steps, you should be able to manually install the STM32Cube firmware successfully.
