iPhone 7 keeps saying "unable to Check for Update" when trying to update to 15.4.1

Just got off the phone with apple. Seems there is a way to load the Iso (14.4.1) thru the windows 10, iTunes app without a complete reset of my iPhone 7.

1) Plug your iPhone 7 into the PC

2) iPhone 7, Press and hold the volume down button and power/sleep buttons at the same time. Keep holding them until you see the recovery mode screen.

3)Start iTunes app on your Window 10 PC.

4) Choose to upgrade (not reset) option from the iTunes appl option.

I have been able to update to iSO 15.4.1 but I still have the other problems associated with this 4000 error code.

e.g. can't sign off user, can't turn off find "My Phone" from iCloud. ,etc.

If this doesn't work then do steps 1-3 again and choose the reset.

Deggie, your 1-6 list doesn't apply to my problem. Thanks for the reply.

My original problem is associated with the 4000 error code that others have reported with the iPhone 7 iOS update to 15.4.1