Windows users needs an additional steps so that the OS can find the Raspberry Pi connected via USB to use fastboot.
It needs Google's USB driver to be manually installed on the Device Manager
Suggestion to add in step 6:
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If you are using Windows, to make fastboot find your device you need the Android USB Driver, download it from https://developer.android.com/studio/run/win-usb
After you plug your Raspberry Pi on your computers USB port, it will be shown as "USB download gadget" on the Windows Device Manager and the command "fastboot devices" won't find anything.
On the Windows Device Manager, right-click the name of the device ("USB download gadget"), and then select Update Driver Software. In the Hardware Update wizard, select Browse my computer for driver software and click Next. Click Browse and then locate the USB driver folder you just downloaded.
Fastboot should be able to find your Raspberry Pi now.
Windows users needs an additional steps so that the OS can find the Raspberry Pi connected via USB to use fastboot.
It needs Google's USB driver to be manually installed on the Device Manager
Suggestion to add in step 6:
=== If you are using Windows, to make fastboot find your device you need the Android USB Driver, download it from https://developer.android.com/studio/run/win-usb After you plug your Raspberry Pi on your computers USB port, it will be shown as "USB download gadget" on the Windows Device Manager and the command "fastboot devices" won't find anything. On the Windows Device Manager, right-click the name of the device ("USB download gadget"), and then select Update Driver Software. In the Hardware Update wizard, select Browse my computer for driver software and click Next. Click Browse and then locate the USB driver folder you just downloaded. Fastboot should be able to find your Raspberry Pi now.