This sounds good, although a little too simple. I could not recreate it but I could be just doing it wrong so:
Do you still have Hibernation activated instead of sleep mode?
Do you have it turned on or turned off/in hibernation when plugging it in, removing cover, removing charger, connecting cover?
Or most importantly, are you still able to do so?
And one last question, does the type cover work for you in the BIOS? :)
I still have sleep mode disabled, though I'm not sure if that makes a difference.
The computer needs to be on, I was in Windows 10 when I performed this.
Prior to being able to get my type cover working again, it was completely unresponsive in Windows as well as in the bios. Previously, the only way I was able to get it working again was by draining the battery and then waiting up to 24 hours before the
keyboard would work again.
On a side note, this is clearly a firmware issue related to the power state of the SP3 and communication of the type cover port. As soon as the type cover loses connection or power, communication with the port stops until the battery has completely drained and erased whatever memory state was holding the port information. Hence why I tried shorting the two power nodes on the type cover port on the SP3.
I thought it was too simple as well, that's why I needed others to test. So far, it has continued to work for myself and it seems another on this forum as well. It's possible that you have a different (although similar) issue with your type cover. Maybe
give my suggestion another try?