'fastboot: unkown option -- i' when attempting to unlock bootloader (Sony XZ)

[Zayan Khan]

Hey everyone. I am using Sony XZ and I am trying to unlock my bootloader (for the past couple of days). I've been following this guide by Sony: https://developer.sony.com/develop/open-devices/get-started/unlock-bootloader/ and I have one problem at question 3. Where it says the following:

• Windows users: When asked for a driver, open the Devices and Printers directory, click on the fastboot driver and press Update. Browse and point towards the location of the new android_winbus.inf file.

So I can't find the winbus file, so I said "Eh, what's gonna happen", so I continue amd enter the unlock code, cmd prompt says

• fastboot:unkown option -- i

So, how do I fix it
Note: I've got the Platform Tools and Google USB Driver (latest version) and I installed a driver on my phone (adb driver I believe)