OK I think I catch what's your problem.
First of all is ask you one thing. Did you keep the phone at edl mode all the time (meaning you did not reboot the phone on each try) while trying to connect to your PC?
I managed to replicate your issue and I saw the same error as you. I believe you have to restart to edl mode each time you want to "first plug" to your computer.
Also, please have your Mi flash beta running first, before you try the "first plug" thingy.
okie, gonna try it now. So I'll restart my com, run mi flash beta, boot up my phone, power it down, edl mode it, then plug it in, right?


