To downgrade a LEGO® Education SPIKE™ Prime hub, you need to use the Hub Downgrade tool: https://spikelegacy.legoeducation.com/hubdowngrade
To use the hub downgrade tool, you will need to use a Chrome Browser on ChromeOS, macOS, or Windows.
Follow the instructions in the hub downgrade tool to downgrade your hub. Once it has been downgraded, the hub will need to go through one last upgrade step inside the SPIKE Legacy App to be useable in SPIKE Legacy.
Downgrading the SPIKE hub on Windows requires a driver
If you are using Windows, you will need to install a DFU driver on the computer. The Windows operating system, as opposed to macOS or ChromeOS, is not pre-installed with the tools necessary to downgrade a SPIKE Prime hub.
You can use third-party drivers to enable your Windows system to perform a downgrade. It will require administrator rights to install, so users must contact their local organization's IT staff or administrator to help with installation.
After a Hub a downgraded to Spike 2, the DFU driver is not needed, and the Spike 2 hub will work on other Windows laptops without DFU drivers.