I was having the same issue, this is how I fixed it.
As we are not able to get to Single User Recovery Mode by using the key sequence, Command + R + S at startup to run
csrutil disable, it is not taking you to Single User Mode.
Start by booting the computer in standard Single User Mode using Command + S. Once you are at the command-line, run the following command to turn off the dGPU:
Then reboot your computer by running:
The dGPU has been disabled, so we can now access the GUI recovery mode. On reboot hold Command + R, and it will take us to the GUI recovery mode. Once there, click on Utility menu and open Terminal, here we can run the
To make the dGPU fix persistent through the next update, make sure to run the nvram command a second time, then reboot by running:
Boot into Single User Mode with Command + S to continue with the kext moving procedure. Once done, go back to GUI recovery to enable
csrutil, then reboot.
Once Mac fully boots, run nvram one last time as sudo:
sudo nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00
and do multiple reboots to test the machine boots back up properly. I have no issues now.