4WD on 2006 4runner

Hello, I have a dumb question, hoping you could help me with (just bought a 4runner two weeks ago, still learning how to operate 4WD). The other day I was in a parking space and switched to H4 (while parked); the 4wd light kept blinking, so I backed up (while it was transferring to H4), and there was resistance in the rear wheels (it seemed like it anyway); I stopped and went forward and it seemed to go into place.

I looked through manual afterwards and doesn't mention anything about going backwards (if 4WD drive light doesn't stop blinking) from H2 to H4 transfer, but does from H4 to H2. First of all, did I do anything wrong by going reverse when it wasn't fully switched to H4? I did wait a few minutes to see if the light stopped blinking. I've heard about "wind up" with 4WD - I'm hoping I didn't damage any of the 4wd system?

It was only backing out of a parking space when it happened, and it's running fine. Just wanted to get your thoughts?