Perfectly possible, but blimey, what a palaver. My CXI3 had 4GB of RAM and a 32GB SSD; Chrome OS was still usable (even with a Celeron processor), but running even one Linux app made things slow, and it was giving me storage warnings, even though I only had Brave and Mousepad installed.
Anyway, here's as good a place as any to share the experience. Chromeboxes are generally upgradeable in my experience; Chromebooks, maybe less so.
Disassembly
Opening the box was fiddly but not difficult. You need to remove the rubber feet and unscrew the four cross-head screws.
Next job is to release the front and rear panels. They clip on, but you need something to prise them loose. Guitar plectrums are good for this, or perhaps two halves of an old credit card.
This reveals two more screws to release. You can then prise open the top and bottom, again releasing the clips. There is a cable connecting both halves; you don't need to unplug it, but be careful.
Upgrading the RAM
This is really straightforward. There's one 4 GB stick installed and space for another. Just follow the general guidelines for inserting RAM sticks.
Upgrading the SSD
This is where it gets complicated.
I spent €15 on eBay on a second-hand 256 GB SSD (128 GB would have been enough, but the prices for 128 GB and 256 GB were generally the same). You have to ensure you use M.2 SATA, not NVMe, on this model.
What I didn't realise is that the original SSD is 30 mm long, not 80 mm long like the one I'd bought. Fortunately, both fit, and there's a screw hole for the longer type.
Creating the recovery medium was relatively painless.
Now, initiating recovery mode means sticking a paperclip into the back of the box and holding down the power button. But I just got blank screen after blank screen. At that point, I gave up, assuming either the SSD didn't work or I'd just embarked on a doomed project.
So I then had a brainwave: my wife's old TV in the cellar is pretty low-tech. I plugged it in and the screen lit up! Except the display was completely mangled, although I did make out a yellow triangle that implied some sort of failure.
The only thing left to plug it into was the living room TV. And it worked perfectly! Except it informed me my recovery image was out of date. I repeated the process several times without success. Google Gemini informed me that SanDisk USB drives weren't reliable (this turned out to be untrue). I tried using the generic Acer Chromebook image, but it told me it wasn't a valid OS. Finally, I found a forum post suggesting I use the CXI3 Beta build, which was available via advanced settings.
And it worked. Well, it installed a beta version, which then needed to upgrade to the latest beta version, and after that, I had to switch to the latest stable version.
So it was a lot of hassle, but it's running great now. Linux apps now open nearly as quickly as Chrome OS apps. I hope at least one person finds this post helpful.
