All,
Hope my experience might help. I did clean install with Clover and managed to get iMessage working approx 2 weeks ago. Three days ago I logged out and couldn't log back in, get the call Apple message. I spend ages on the phone with Apple and despite them resetting, no good.
I was encouraged reading JBamford's (and others) reports that using MLB and ROM from genuine Mac got them back in and tonight I did same, entering a genuine MLB and ROM into SMBIOS in Clover. I restarted and straight away I can log into iMessage and FaceTime, both working. I then came to this thread to post my news and see JBamford locked out again (sorry to hear dude!)
My question is: I have only changed the MLB and the ROM in SMBIOS and iMessage/Facetime is working as I type, should I enter the other info I have from the genuine iMessage debug e.g. serial number, SMUUID etc or should I leave as is? Concerned that although working tonight I may suffer same fate as JB.
If I can provide any other info in search for longer term solution, let me know what you want.