Surface Pro 4 type cover suddenly not working.

This is a very real problem that Microsoft refuses to address. I have taken my device to my local store, where their employees admitted to me that the Surface Pro 4 is the "black sheep of the Surface line" and their official advice to me was to purchase a third party bluetooth keyboard, or purchase a $600 replacement out of warranty, as if I have any remaining trust in their products. It is so insulting to overspend on their keyboard accessory in the first place just to be told to buy third party. 

I also DM'd their @Microsofthelps twitter who then passed me along to one of their engineers, who continued to misunderstand the issue, thinking that the type cover itself was defective. Furthermore, they keep hammering on this fact that the device is out of date at 3 years of age, as if the Surface Pro 5, 6 and 7 are different and better in any significant way. It may be 3 years old but it was working fine before they pushed an update that bricked it. Just because you slap a new number on this year's device doesn't mean mine is a POS. I should have gotten 5 years of use out of this easily, and that's me being forgiving. At every turn they have made me feel like a fool. 

At no point has Microsoft owned up to this issue or acknowledged that it may be a firmware corruption. All they do is infer user error or misuse and talk to you like you're crazy. "Clean your ports with an alcohol wipe", as if I'm storm chasing tornadoes in duststorms and not just sitting on my couch at home. How can the connecting port even get dirty if you never take the type cover off? 

I know it doesn't mean anything to Microsoft, but I will never again spend any of my money on their devices or hardware. The fact that I have a defective $1100 computer who's functionality is now severely limited, and to not have this problem taken seriously is really demoralizing.

in your scenario, i think you might have a faulty old keyboard and a problematic surface pro.

try my steps and the driver update on the surface pro, with the new keyboard.

try the rotation workaround fix as well, that should fix the issue with the surface pro problem.

That's odd that the old keyboard works on the new Surface. I took my keyboard to a computer shop and asked if I could attach it to one of the new Surfaces.....still didnt work. So, I thought the keyboard was the problem. However, when I bought a new keyboard, that didn't work either!  There seems to be no logic to this issue.

...........bluetooth keyboard WHICH works...........

I have the same issues with my Surface 4.  I took it to a tech because nothing I did fixed the problem. He even did a full re-install after he couldn't find the problem.  Still nothing!   I even borrowed someone's spanking new type cover used on her equally brand new Surface (6 ?).  Still nothing.

I do have a bluetooth keyboard with works, however, I've lost the convenience of having a cover plus an unattached keyboard is a pain if you are using the Surface on your lap.

I've come to the conclusion that, despite everyone's complaints, Microsoft just isn't interested in fixing the issue.....they want you to upgrade to the latest Surface, as if we all have a stack of money to throw around on buying a replacement for a computer that still works just fine.