E-Kur-Mah: Sudran Key & Red Coat

From the topmost room of Kur, use your Drone Teleport (a tool that allows you to send a remote drone to interact with the environment) in the top left corner to collect the note titled 1:From the High Priestess.

Use Drone Teleport again to reach the door on the right side and proceed to the next area.

Encounter a difficult enemy; use Address Bombs to make them harmless and afraid of you.

Head to the lower middle part of this room and drill into the right column to find the note titled 2:Anonymous Quote.

Exit through the door in the ceiling and follow the linear path to a large room.

The bottom left door leads to a save room (a place where you can save your progress). Use it.

Go right and follow the path. Drill into the bottom right corner to find the note titled 3:The Land of Civilized Kings.

Go to the top of the room and drill straight down the middle of the right mass of blocks underneath you.

After passing two white blocks sticking out of the right wall, start drilling right to find the 4:Sudran Key.

Backtrack up and left two rooms to find that 5:Power Node 6 of 6 is now accessible.

Backtrack to the first room of the area.

The lower right door is now open thanks to the Sudran Key. Take this path as far right as possible to find another save point. Save your game.

Head down the next three vertical rooms, saving at the next save point.

Go through the bottom left door in the save room and navigate the winding path in the giant room. Without the Passcode Tool upgrade, you cannot access one square on the map or the Quantum Variegator weapon.

Reach the bottom, go down a couple of rooms, and follow the path, drilling as necessary to reach the 6:Red Coat upgrade. This upgrade allows you to warp farther and faster and leaves a damaging trail that can instantly destroy drillable blocks.

Use the Red Coat to break blocks inside a wall below to find 7:Power Node Fragment 5 of 18.

Backtrack to the large room above and head right along ground level.

Where the ceiling has a gap, shoot your Drone up and fire upward when it activates to break blocks. Repeat to clear a path to a small pathway up right.

Shoot the Drone up into this pathway to find 8:Health Node Fragment 10 of 20 at the end.

Backtrack to the first vertical room you went down between the two save points.

Collect the note titled 9:Official Letter, which is now accessible thanks to the Red Coat.

Double-backtrack to the lower save point and take the upper left door to return to Kur.