Audio is muted because I listened to the album Days of future passed.

I used the Green Beam Glitch, which is not really a glitch. It's just the game, when teleporting from a stable platform, create shortly an invisible platform where you can jump, certainly to not frustrate the player who can't time his jump. Good for us, eheh. So, basically, at the end of the beam, you have a short window to move to one direction then jump and fly past the bloc. Really useful. And you can jump on those friable blocks (But it's really difficult to time it right.)

So the sub7 is possible, with enough practice. Have fun!