On the back of my Samsung Chromebook, cheap one, not the 550, there are 4 slots on the back. Three are labeled, one has a door. There is an HDMI, a SS USB, and a normal USB. The one with a door that looks like it has a rubber piece already in it is a SIM slot for what could have been 3G or 4G broadband. This door is to the left of all the other ports. The SD card slot is on the left side of the system and is labeled SD. I don't know of any Chromebook right off hand that has a MicroSD slot and especially not on the back. All of them seem to have the SD or memory card slots on the left or right side.
What model do you have and what is the slot labeled?
Which Chromebook? – Paul – 2013-09-06T04:04:44.663