SD Cards and Writing Images

Contributors: M-Short
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SD Cards

SD Cards can be found most everywhere, online, at your local store. But whats sets one apart from the rest? What makes a good SD card? Besides manufacture, the main differences between cards are physical size, capacity/standards, and speed. Here is a brief overview of each of those elements.


SD cards come in two main sizes. Full sized SD cards are used in digital cameras all over the globe, and microSD (often called µSD or uSD) cards are used in cellphones and tablets, amongst others. Electrically they are the same thing, though. Ever notice the cheap plastic adapters that come with some microSD cards? They are nothing more than a plastic shell with connectors to pass through the microSD connectors to the full size connectors. Installing images on them is the same, just make sure you have the right card (and adapter, if needed) for your device and reader.


There are actually 4 different standards of SD card, with each new version came higher capacity and often higher speeds. The 4 versions are: Standard or SD (up to 4GB), High Capacity or SDHC (up to 32GB and formatted as FAT32), Extended High Capacity or SDXC (up to 2TB and formatted as exFAT), and SDIO (has support for I/O). Any of these should work but be careful with SDXC cards; because of licensing issues, not all devices can support exFAT.


Most cards will also list a class or speed on them to distinguish how fast they can read and write. Class 2,4,6,8 and 10 are 2MB/s, 4MB/s, 6MB/s, 8MB/s, and 10MB/s, respectively. UHS Class 1 and UHS Class 3 are 10MB/s and 30MB/s, respectively. For the most part, these numbers are irrelevant; just keep in mind that there are different speeds so if things are running slower than you'd like, check the card.

For this tutorial, any of these cards will work with. However, make sure you have the correct physical size for your device, and the the card has a high enough capacity to hold the image you want to use. This 8GB card should work for just about everything since it has an SD adapter as well as a card reader.

SD cards, uSD cards, uSD adapters, and Wifi enabled SD card

SD cards, uSD cards, uSD adapters, and Wifi enabled SD card