Try pushing blocks. 
Thanks. I find the my way to solve this challenge to be quite creative. Here are steps to render it offcial solution in future updates:
1. Make secrets temporary in this screen.
2. Put a hint slab on the top wall that tells player that he needs to be very fast here (requires Farore`s boots).
3. Render the blocks in the top row non-pushable.
4. Put a staircase under the bottom black block (pushable) that sends Link to previous area trough one-way passage.
P.S. The way you hid one of the keys in level 6 (prior to minecart) is quite cruel. Figured it out at pure accident.. I am suggesting to put Lens Marker flags on both combos of that false root-like wall.
P.P.S Currently at level 8, got the fire rod and the Murmasa (prior to entering L7). Where I should go now?
Bumping this topic real quick. I've been going through Level 6, and I came across this room:

How do I get over to the other side? I assume I need to fall from above but I honestly have no idea.
There is a false wall in one of the screens on the path to this screen. Look behind green roots.