Using the https://support.lenovo.com/au/en/solutions/lnvo-xpress Will give you the individual firmware files to update via IMM. However this doesn’t work with Windows 10 due to : 

This launchpad is not intended to run on the current platform. Check the product documentation or contact your vendor for more information about supported platforms.

You can run the tool via command line e.g. lnvgy_utl_uxspi_10.3_winsrvr_32-64.exe acquire -L 

However it’s each to run the Download Bootable Media Creator

Download and Run 

https://support.lenovo.com/au/en/solutions/lnvo-bomc

Run as Admin and create an ISO 

Map this using the IMM ( Via IE )