Boost Block

A Boost Block, also known as Speed Booster Block or Dash Block, is a type of block that can only be destroyed by using the Speed Booster, Shinespark, or Ball Spark. They are found in Super Metroid, Metroid Fusion, Metroid: Zero Mission, and Metroid Dread.

In Dread, some obstacles with Boost Blocks are marked with yellow cracks, providing a subtle clue without needing to identify them using bombs or missiles. This is similar to Screw Attack Blocks, which are frequently marked with blue cracks. Unlike previous games, Boost Blocks are permanently destroyed, and Samus only needs to break one block to destroy all connected blocks in a chain reaction.

Official data

Super Metroid manual

"Blocks with the Speed Booster icon melt away when Samus runs into or over them at super speed."

Metroid Fusion manual

BOOST BLOCKS

"Break through Boost Blocks after recovering the Speed Booster. Reaching the necessary speed requires some distance, so start running in the room next to the room containing Boost Blocks."

Metroid Zero Mission manual

Boost Blocks

"Break through Boost Blocks by acquiring the Speed Booster and then charging through the blocks at supersonic speed. Reaching the necessary speed requires some distance, so you may have to start running from the next room over."

Metroid Fusion: The Official Nintendo Player's Guide

Dash Block

"Destroy with a Speed Booster run."

Metroid Prime and Metroid Fusion: Prima's Official Strategy Guide

Boost Blocks

"A Boost Block can only be destroyed when Samus is using Speed Booster. The easiest technique is to simply clear a room of obstacles and enemies, and run in the direction of the Boost Blocks. If Speed Booster is engaged, Samus will blast through the blocks. This will get you through most of the early Boost Block placements.
However, as you advance through the levels, you'll need to master the art of changing direction in the middle of a Speed Booster run. In the sequence picture above, the first step is to solve the puzzle of connecting the platforms (this is explained in the walkthrough). After running to initiate Speed Booster, you must pause (tap [Down] on the +Control Pad). Next, tap [A] to jump up to the level of the Boost Blocks. Finally, continue Speed Booster by pressing and holding [Right] on the +Control Pad.
Some Speed Booster runs must sustain through several sets of Boost Blocks, as picture above. So, don't give up on the run until Samus slams into something solid.
NOTE: You can pause a Speed Booster run at any time, by tapping [Down] on the +Control Pad, which forces Samus into a crouch. You have a couple seconds to resume the run by tapping the Jump key [A] (Samus lifts her feet). Continue the Speed Booster by pressing one of the directional buttons on the +Control Pad (this includes [Left-Down], [Right-Down], [Left-Up], and [Right-Up] for angled movement). You can repeat this process an unlimited number of times, as long as Samus does not hit a wall or obstalce.
While Samus is in a crouch, you can also morph into a ball to navigate tight quarters. When you want to return to Samus's normal form, tap +Control Pad [Down] again, and then repeat the process to resume the run. Hence, when you uncover Boost Blocks, you must examine all possible routes to your target. In the later levels, this is rarely a straight path."

Metroid: Zero Mission: The Official Nintendo Player's Guide

SPEED BOOSTER BLOCKS

"Speed Booster Blocks break on contact with a dashing adventurer. You'll build your Speed Booster's charge by running for the width of a few screens. While charging, you can fly through blocks in the floor, walls or ceiling. If you kneel to stop (press Down), you can sustain the charge for a few seconds. When you're ready to take off again (in standing or Morph Ball form), tap the A Button, then hold the Control Pad Left, Right, Up or diagonally."

Gallery

Beta Fusion version with two yellow arrows

Yellow cracks in a wall consisting of Boost Blocks in Dread