@Manoj can you please have a look at the thread already linked by @AnotherElk → Following the official install guide did not work at all for me and others but there are workarounds (please note #14 as well as the OP). This is either a hiccup in the current version of the install script or one would need to be guided properly as to how to be in the fastbootD mode (and not regular bootloader mode in which you end up if you follow the guide; and even then there are issues that need to be worked around.)
Thanks a lot for all your support! 