There’s been a marked trend towards modern tablets and phones having fewer expansion options. It’s becoming rarer to find a microSD slot available, which can be particularly frustrating. For [davisr], this simply wouldn’t do, and they set about hacking their ReMarkable tablet.
The ReMarkable already has a set of pads for an SDHC interface on the main board, ready to go. Despite this, both hardware and software modifications are required to get things up and running. [davisr] started by soldering some wires to the main board, feeding them to a microSD socket, which was mounted on the edge of the tablet in a convenient nook. The case was then delicately modified to make a slot for cards to be inserted and removed. With this done, the kernel was then recompiled to enable support for the SDHC interface, and everything was up and running.
With the modification in place, [davisr] now has over 150GB of storage available, which should last for quite some time. Similar hacks are possible on other platforms, too. Even the Pi Zero can mount a second SD card with the right mods!
It seems that, if he wanted to keep the card in the inside of the tablet, he could have just solderered the slot directly in the mainboard.
The first sentences of the linked article:
“This page discusses how I added a microSD card to my reMarkable tablet. I did this because I want to develop software for my rM without wearing out the internal eMMC. I chose an external card because I want to be able to swap them easily; it also makes backups faster.”
Huge fan of reMarkable here, great hack. Look forward to the apps davisr will hopefully share!
Gotta say, with such placement, it’s not impossible that the card will break in two pieces if the tablet is i.e. put in a bag, or carried around carelessly. I’ve had MicroSD cards break, either just snapping off a piece or developing near-invisible fractures (no longer working either way), all because of card positioning done like this when designing my homebrew devices. In short, make sure your MicroSD cards don’t stick out.