I got this ARM-based Chromebook for little money, so I thought I’d have a go with Linux on it. It is quite small and lightweight, almost like those Ultrabooks, but much cheaper, in every respect.
TODO: Copying the old system, installing Debian, make Flash work TODO: my scripts
Convert SD to MicroSD card slot
Linux works well on the Chromebook, but 16 GB of internal storage is a bit short. Luckily, the Samsung Chromebook has an SD card slot for expansion storage. I set up my Linux so that it puts all directories that are normally written to on the external SD card, effectively using the internal storage as a read-only memory.
Well, but due to space constraints or evil attempts on Samsung’s side to limit the usability of the SD card slot, a normal SD card protrudes by 2/3 of the card’s length from the Chromebook when inserted. :-/ The MacBook Air has the same issue, probably because of the similar reasons: Buy more internal, expensive storage instead of expanding it yourself… Some clever people came up with an MicroSD to SD adapter card that is so short, it is flush with the case when inserted. Well, but in the Chomebook, the card still protrudes from the curvesd bottom, although is doesn’t protrude from the side.
After all, the only feasible way to use an SD card without protrusion is to mount it inside the case, so let’s open the device.
Replacing the card slot
Remove all feet, unscrew all now visible screws from the bottom. Remove the rear bezel gently, then proceed with the bottom. Disconnect all connectors, especially the battery. Unscrew the four screws that hold the main board, remove it.
Now, let’s proceed with the card slot (left third of the picture). Unsolder the card slot, starting at the edge of the board with the large pads. A good soldering iron and a thin piece of steel to lift the pins individually from the pads is handy. Hot air also works if you preheat the PCB before, but I switched to my soldering iron because the PCB drew away the heat from the air gun too quickly.
After you successfully removed the card slot without damaging the solder pads, clean them and solder some small copper wires to them. I made the power lines (see middle part) of 0.5mm thick copper while the other wires had about 0.25 mm diameter. Take care to solder the large pads at the top edge to their corresponding pad at the bottom row: The left wire is the write lock, without it, you can’t write to your SD card. The right one may be unnecessary, but to be sure, just solder it. Put some Polyimide (“Kapton”) tape on the soldered pads to insulate them from and the traces below from hot glue or any other metal particles, just to be sure.
Take some MicroSD-to-SD adapter, they are all about the same. Cut the plastic at the beveled edge so that the adapter doesn’t protrude from the PCB, but fits. The white 3-pin connector for the speaker (right below the adapter) is the limiting part here. When the card fits, heat up your hot snot gun and quickly glue the adapter at the left and right edge to the PCB, pressing it down firmly. If you look carefully, you see that my hot glue has glitter particles. Isn’t that beautiful. :-D The adapter should now be firmly attached to the PCB. I chose to glue the sides of the card because the middle part is so thin that it may bend while gluing, making it hard to impossible to insert a card. Now, bend around all copper wires and solder them 1:1 to their corresponding pins.
Congratulations, you now have a Samsung Chromebook with integrated MicroSD card slot! Mount the finished board inside the case, plug all connectors in, insert an MicroSD card and boot the machine.
If you ever want to change the SD card, you have to pry it from the slot with tweezers, but hey. That’s a good compromise for having no protruding parts anymore on your Chromebook! :-)